Monocarbonyl ruthenium and osmium catalysts

ABSTRACT

The invention relates to monocarbonyl complexes of ruthenium and osmium with bi- and tridentate nitrogen and phosphine ligands. The invention relates to methods for preparing these complexes and the use of these complexes, isolated or prepared in situ, as catalysts for reduction reactions of ketones and aldehydes both via transfer hydrogenation or hydrogenation with hydrogen.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.17/673,220, filed Feb. 16, 2022, which is a divisional of U.S. patentapplication Ser. No. 16/075,315, filed Aug. 3, 2018, now U.S. Pat. No.11,278,876, issued Mar. 22, 2022, which is a US national phase ofInternational Patent Application No. PCT/IB2017/050598, filed Feb. 3,2017, which claims priority of Italian Patent Application No.102016000011905, filed Feb. 5, 2016, the disclosures of which areincorporated by reference herein.

The invention relates to monocarbonyl complexes of ruthenium and osmiumwith bi- and tridentate nitrogen and phosphine ligands. The inventionrelates to methods for preparing these complexes and the use of thesecomplexes, isolated or prepared in situ, as catalysts for reductionreactions of ketones and aldehydes both via transfer hydrogenation orhydrogenation with hydrogen.

STATE OF THE ART

The carbonyl compounds (aldehydes and ketones) can be easily reduced toalcohols by molecular hydrogen (hydrogenation) or hydrogen donormolecules (transfer hydrogenation) through the use of catalysts based onrhodium, iridium, iron, ruthenium and osmium.

The development of complexes that catalyze the chemo- andstereo-selective reduction of carbonyl compounds is a subject ofconsiderable academic and industrial interest, a target which can beachieved through the fine-tuning of the ligands of the complexes.

The hydrogenation, which entails the use of hydrogen under pressure, isan industrial process for the synthesis of alcohols. A significantbreakthrough for the development and application of this process wasgiven in the late '90s by a new class of ruthenium complexes of formulaRuCl₂(P)₂(diamine) and RuCl₂(PP)(diamine) (P=phosphine andPP=diphosphine) for the catalytic enantioselective hydrogenation ofketones. By using a suitable combination of chiral diphosphine anddiamine ligands, these complexes were proven to efficiently catalyze theasymmetric reductions of carbonyl compounds with production of chiralalcohols with high enantiomeric excess.

In addition to hydrogenation, the transfer hydrogenation reaction hasalso been developed using 2-propanol or formic acid as hydrogen source,with the advantage of employing non-pressure systems and reducing therisk.

In 2004 Baratta and collaborators have developed ruthenium complexescontaining phosphines and bi- and tri-dentate aminopyridine ligandswhich show high catalytic activity in hydrogenation and transferhydrogenation reactions.

Recently, the complexes trans-RuCl₂(CO)(NN)(PR₃) (R═Ph, p-tolyl;NN=ethylenediamine, 2-aminomethylpyridine and bipyridine) were isolatedand they were found active in the transfer hydrogenation of ketones (D.A. Cavarzan et al., Polyhedron 2013, 62, 75). It is worth noting thatthe carbonyl complexes [RuX(CO)(NN)(PP)]CI (X═CI, H; NN=ethylenediamineor 2-aminomethylpyridine) and RuCl(CP)(CO)(NN) containing acyclometallated phosphine (CP) isolated by Baratta and co-workersdisplay high catalytic activity in the transfer hydrogenation of ketones(S. Zhang et al., Organometallics 2013, 32, 5299; W. Baratta et al.,Angew. Chem. Int. Ed. 2004, 43, 3584; W. Baratta et al., Organometallics2004, 23, 6264 and WO2005/051965). Complexes of the formulaRuCl₂(CO)(dmf)(PP) have been found active in hydrogenation, transferhydrogenation, hydroformylation and carbonylation reactions(WO2012/123761 A1).

The interest in these systems stems from the fact that the presence of aRu—CO bond makes the catalyst more robust and less sensitive to thedecarbonylation reactions of the substrates which can deactivate thecatalysts, preventing their use in very low quantities.

Moreover, to make the reduction of carbonyl compounds to alcoholseconomically competitive, via transfer hydrogenation or hydrogenation,the development of catalysts with high chemo- and stereoselectivity is acrucial issue. Furthermore, the catalysts have to display highproductivity and should be easily prepared from commercially availablestarting material through simple and safe synthetic routes.

The purpose of the present invention relates to the synthesis ofcomplexes of ruthenium and osmium containing a CO ligand in combinationwith bidentate and tridentate nitrogen ligands and achiral or chiralphosphines. These complexes can be used as catalysts in the (asymmetric)reduction of carbonyl compounds by transfer hydrogenation orhydrogenation with molecular hydrogen.

A further object of the present invention is to obtain ruthenium (II)and osmium (II) complexes which can be generated in situ during thereduction of carbonyl compounds or by transfer hydrogenation orhydrogenation with molecular hydrogen.

SUMMARY OF THE INVENTION

In order to achieve the purposes mentioned above the inventors haveidentified in a series of monocarbonyl complexes of ruthenium andosmium, containing nitrogen and phosphine ligands, the solution forobtaining catalysts with high catalytic activity in hydrogenationreactions with molecular hydrogen and transfer hydrogenation of carbonylcompounds to alcohols.

Accordingly, the present disclosure refers to a pentacoordinate orhexacoordinate complex of formula (1):

[MXY_(a)(CO)L_(b)L′_(c)]W_(d)   (1)

-   wherein-   M=Ru or Os;-   a, b and d are independently 0 or 1;-   c is 1 or 2;-   X, Y are independently selected among halides, hydride, C1-C20    carboxylates and C1-C20 alkoxides;-   W is selected among halides, C1-C20 carboxylates and C1-C20    alkoxides;-   L is a nitrogen-containing ligand selected among:-   (I) a NN compound of formula Ia to Ic:

-   (II) a HCNN compound of formula IIa-IIb and a CNN ligand of formula    IIc-IId:

-   (III) a HCN compound of formula IIIa

-   wherein-   R¹-R¹⁵ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups;-   L′ is at least one phosphorus-containing ligand selected among:-   a phosphine (P) selected among: a phosphine of formula PR¹⁶R¹⁷R¹⁸,    wherein R¹⁶-R¹⁸ are independently selected among H, C1-C20 aliphatic    groups and C5-C20 aromatic groups; an optically active phosphine    selected among (S)-neomenthyldiphenylphosphine and    (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl;-   a diphosphine (PP) selected among: a diphosphine of formula    P(R¹⁹)₂—Z—P(R²⁰)₂, wherein Z is a C2-C4 aliphatic group or ferrocene    optionally substituted with C1-C20 aliphatic groups, and wherein R¹⁹    and R²⁰ are independently selected among C1-C20 aliphatic groups and    C5-C20 aromatic groups; an optically active diphosphine selected    from the group consisting of    (R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine],    (R)-(1,1′-binaphthalene-2,2′-diyl)bis(diphenylphosphine),    (R)-(1,1′-binaphthalene-2,2′-diyl)bis[bis(3,5-dimethylmethyl)phosphine],    (R)-1-{-2-[diphenylphosphine]ferrocenyl}ethyldicyclohexyl phosphine,    (R)-1-{-2-[bis(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocenyl}ethyldicyclohexyl    phosphine and (2R,4R)-2,4-bis(diphenylphosphine)pentane;-   a HCP compound of formula (IVa) and a CP ligand of formula (IVb)

-   a PNN compound of formula (V)

-   wherein-   R²¹-R²⁹ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups;-   provided that:-   when a=b=c=1; d=0; X═Y═Cl; L is ethylenediamine or    2-(aminomethyl)pyridine or 2,2′-bipyridine or    4,4′-dimethyl-2,2′-bipyridine, L′ is not a phosphine (P) of formula    PR¹⁶R¹⁷R¹⁸ in which R¹⁶═R¹⁷═R¹⁸=phenyl or p-tolyl;-   when a=0; b=c=d=1; X═W═Cl or X═H and W═Cl, L=ethylenediamine or    2-(aminomethyl)pyridine, L′ is not Ph₂P(CH₂CH₂CH₂)PPh₂;-   when a=d=0; b=c=1; X═Cl; L=ethylenediamine or    2-(aminomethyl)pyridine, L′ is not a ligand (CP) of formula (IVb) in    which R²¹═R²²=phenyl and R²³=methyl; and-   when a, b and d are 0, c is 2, X is Cl and R²³ is —CH₃, R²¹ and R²²    are not phenyl groups.

In a further aspect, the present disclosure refers to the use of saidruthenium or osmium complexes as catalyst or pre-catalyst for thereduction reaction of ketones or aldehydes to alcohols by transferhydrogenation or hydrogenation with molecular hydrogen.

This and other aspects as well as the characteristics and advantages ofthe present invention will be more apparent from the detaileddescription below and by the preferred embodiments given as non-limitingillustrations of the invention itself.

DESCRIPTION OF THE INVENTION

As used therein, “aliphatic group” refers to acyclic or cyclic, linearor branched, saturated or unsaturated hydrocarbons, excluding aromaticgroups.

As used therein, “substituted aliphatic group” refers to an aliphaticgroup in which at least one hydrogen atom is replaced by at least onesubstituent group selected among —OR, —NRR′, —NRCOR′, —NO₂, —NH₂, —COR,—COOR, —CONRR′ and halides, wherein R and R′ are equal or different andcan be a H or a C1-C20 aliphatic or aromatic group.

As used therein, “aromatic group” also include aromatic compoundssubstituted with aliphatic groups.

As used therein, “substituted aromatic group” refers to an aromaticgroup in which at least one aromatic hydrogen atom is replaced with atleast one substituent group selected among —R, —OR, —NRR′, —NRCOR′,—NO₂, —NH₂, —COR, —COOR, —CONRR′ and halides, wherein R and R′ are equalor different and can be a H or a C1-C20 aliphatic or aromatic group.

As used therein, “heteroaromatic group” refers to aromatic groups inwhich at least one carbon atom which is part of the aromatic ring isreplaced with one heteroatom selected among N, S, O and P.

As used therein, “hydrogen-donor” refers to a compound that transfers ahydrogen atom to another compound.

As used therein, “(transfer)hydrogenation” refers to hydrogenation withmolecular hydrogen or to transfer hydrogenation using a hydrogen donorcompound.

In the present description and appended claims the abbreviations listedin Table 1 are used:

TABLE 1 Abbreviation of the nitrogen and phosphorus ligands Chemicalname Abbreviation Structural formula Nitrogen-containing ligand Lethylenediamine en

2-(aminomethyl)pyridine ampy

bipyridine bipy

(1R,2R)-1,2- diphenylethylenediamine (R,R)- dpen

(1S,2S)-1,2- diphenylethylenediamine (S,S)- dpen

6-(4-methylphenyl)-2- (aminomethyl)pyridine Hamtp

Anionic form of 6-(4- methylphenyl)-2- (aminomethyl)pyridine amtp

2- (aminomethyl)benzo [h]quinoline Hambq

Anionic form of 2- (aminomethyl)benzo [h]quinoline ambq

4-phenyl-2- (aminomethyl)benzo [h]quinoline Hambq^(Ph)

Anionic form of 4-phenyl-2- (aminomethyl)benzo [h]quinoline ambq^(Ph)

benzylamine HCN

Anionic form of benzylamine CN

phosphorus-containing ligand L′ triphenylphosphine PPh₃tricyclohexylphosphine PCy₃ triisopropylphosphine PiPr₃ 1,3-bis(diphenylphosphino) propane dppp

1,4-bis (diphenylphosphino) butane dppb

1,1′-bis (diphenylphosphino) ferrocene dppf

(R)-1-[(S_(P))-2- (diphenylphosphino) ferrocenylethyl] diphenylphosphine(R)- Josiphos

(R)-(+)-2,2′- bis(diphenylphosphino)- 1,1′-binaphthalene (R)- BINAP

(R,R)-Skewphos (R,R)- BDPP

(2,6- dimethylphenyl) diphenylphosphine Hdmpp

Anionic form of (2,6- dimethylphenyl) diphenylphosphine dmpp

(2,6- dimethylphenyl) dicyclohexylphosphine Hdmppc

Anionic form of (2,6- dimethylphenyl) dicyclohexylphosphine dmppc

PNN

The present disclosure refers to a pentacoordinate or hexacoordinatecomplex of formula (1):

[MXY_(a)(CO)L_(b)L′_(c)]W_(d)   (1)

-   wherein-   M=Ru or Os;-   a, b and d are independently 0 or 1;-   c is 1 or 2;-   X, Y are independently selected among halides, hydride, C1-C20    carboxylates and C1-C20 alkoxides;-   W is selected among halides, C1-C20 carboxylates and C1-C20    alkoxides;-   L is a nitrogen-containing ligand selected among:-   (I) a NN compound of formula Ia to Ic:

-   (II) a HCNN compound of formula IIa-IIb and a CNN ligand of formula    IIc-IId:

-   (III) a HCN compound of formula IIIa

-   wherein-   R¹-R¹⁵ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups, preferably R¹ and R² may be    independently selected among H and a phenyl group and/or R³-R⁶ and    R⁸-R¹⁵ may be H and/or R⁷ may be 4-methyl;-   L′ is at least one phosphorus-containing ligand selected among:-   a phosphine (P) selected among: a phosphine of formula PR¹⁶R¹⁷R¹⁸,    wherein R¹⁶-R¹⁸ are independently selected among H, C1-C20 aliphatic    groups and C5-C20 aromatic groups; an optically active phosphine    selected among (S)-neomenthyldiphenylphosphine and    (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl;-   a diphosphine (PP) selected among: a diphosphine of formula    P(R¹⁹)₂—Z—P(R²⁰)₂, wherein Z is a C2-C4 aliphatic group or ferrocene    optionally substituted with C1-C20 aliphatic groups, and wherein R¹⁹    and R²⁰ are independently selected among C1-C20 aliphatic groups and    C5-C20 aromatic groups; an optically active diphosphine selected    from the group consisting of    (R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine],    (R)-(1,1′-binaphthalene-2,2′-diyl)bis(diphenylphosphine),    (R)-(1,1′-binaphthalene-2,2′-diyl)bis[bis(3,5-dimethylmethyl)phosphine],    (R)-1-{-2-[diphenylphosphine]ferrocenyl}ethyldicyclohexyl phosphine,    (R)-1-{-2-[bis(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocenyl}ethyldicyclohexyl    phosphine and (2R,4R)-2,4-bis(diphenylphosphine)pentane;-   a HCP compound of formula (IVa) and a CP ligand of formula (IVb)

-   wherein-   R²¹-R²³ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups, preferably R²³ may be —CH₃ and/or    R²¹-R²² may be C6-C20 cycloaliphatic group or C6-C20 aromatic group,    more preferably R²³ may be —CH₃ and/or R²¹-R²² may be independently    selected among phenyl and cyclohexyl group-   a PNN compound of formula (V)

-   wherein-   R²⁴-R²⁹ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups, preferably R²⁴ and R²⁷-R²⁹ may be H    and/or R²⁵ and R²⁶ may be a C1-C20 aromatic group, more preferably a    phenyl group;-   provided that:-   when a=b=c=1; d=0; X═Y═Cl; L is ethylenediamine or    2-(aminomethyl)pyridine or 2,2′-bipyridine or    4,4′-dimethyl-2,2′-bipyridine, L′ is not a phosphine (P) of formula    PR¹⁶R¹⁷R¹⁸ in which R¹⁶═R¹⁷═R¹⁸=phenyl or p-tolyl;-   when a=0; b=c=d=1; X═W═Cl or X═H and W═Cl, L=ethylenediamine or    2-(aminomethyl)pyridine, L′ is not Ph₂P(CH₂CH₂CH₂)PPh₂;-   when a=d=0; b=c=1; X═Cl; L=ethylenediamine or    2-(aminomethyl)pyridine, L′ is not a ligand (CP) of formula (IVb) in    which R²¹═R²²=phenyl and R²³=methyl; and-   when a, b and d are 0, c is 2, X is Cl and R²³ is —CH₃, R²¹ and R²²    are not phenyl groups.

In complexes of formula (1), when c=2 and L′ represents twophosphorus-containing ligands independently selected among thephosphorus-containing compounds listed above, when one L′ is CP and oneL′ is HCP, the complex of formula (1) is pentacoordinate complex.

The high modularity of the nitrogen-containing ligands (Ia-c), (IIa-d)and (IIIa) in combination with phosphines (P), diphosphines (PP), HCPphosphines and PNN phosphines, allows to obtain a large number ofwell-defined catalysts displaying high chemo- and stereoselectivity.

For the purposes of the present invention, from the combination of thedifferent meanings of X, Y, W, L, and L′, the complexes of sub-formulas(VI-XIV) given below may be obtained, which are encompassed by thegeneral formula (1).

According to an embodiment, the bidentate (NN) ligands of type (Ia-c)have the ability, through the nitrogen atoms of a —NH₂ group or of aheterocycle in combination with monodentate phosphines, to coordinatethe metal. Thus, the present disclosure may refer to a complex offormula (VI)

MXY(CO)(NN)(P)   (VI)

wherein M, X, Y, (NN) and (P) are as defined above, provided that when Xand Y are Cl, R¹⁶-R¹⁸ are not phenyl or p-tolyl groups.

According to a specific embodiment, the present disclosure may refer tocomplexes of formula (VI) wherein M, X, Y, (NN) and (P) are as definedabove, provided that when X and Y are Cl, R¹⁶-R¹⁸ are not aromaticgroups.

Complexes of formula (VI) can be obtained as a mixture of trans-isomers(eg. complex 4 and 6 below) and cis-isomers (eg. complex 5 and 7).

The present disclosure also refers to a process to obtain complexes offormula (VI) comprising reacting a compound of formula MXY(CO)(PPh₃)₂,or of formula MXY(CO)(PPh₃)₂(dmf), wherein M, X, Y are as defined aboveand (dmf) is dimethylformamide, with a phosphine (P) selected among:

-   phosphines of formula PR¹⁶R¹⁷R¹⁸, wherein R¹⁶-R¹⁸ are independently    selected among H, C1-C20 aliphatic group and C5-C20 aromatic groups;    and-   an optically active phosphine selected among    (S)-neomenthyldiphenylphosphine and    (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl;-   and at least one nitrogen-containing compound NN selected among

wherein

-   R¹-R⁶ are independently selected among H, C1-C20 aliphatic group and    C5-C20 aromatic group, preferably R¹ and R² may be independently    selected among H and a phenyl group and/or R³-R⁶ may be H. Compounds    of formula MXY(CO)(PPh₃)₂ or of formula MXY(CO)(PPh₃)₂(dmf) may be    prepared by reacting compounds of formula MXY(PPh₃)_(k), wherein k    is 2 or 3 with carbon monoxide, in the presence of a suitable    organic solvent and optionally of dimethylformamide.

According to an embodiment, when X═Y═Cl, the compoundMCl₂(CO)(PPh₃)₂(dmf) may be formed by reacting MCl₂(PPh₃)₃ with CO inthe presence of dimethylformamide and a suitable organic solvent. When Mis Ru, the compound RuCl₂(CO)(PPh₃)₂(dmf) may be formed by reactingRuCl₂(PPh₃)₃ with CO in the presence of dimethylformamide and a suitableorganic solvent.

According to an embodiment, when X═Y=acetate (OAc), the compoundM(OAc)₂(CO)(PPh₃)₂ may be formed by reacting M(OAc)₂(PPh₃)₂ with CO inthe presence of a suitable organic solvent. When M is Ru, the compoundRu(OAc)₂(CO)(PPh₃)₂ may be formed by reacting Ru(OAc)₂(PPh₃)₂ with CO inthe presence of a suitable organic solvent.

Compounds such as RuCl₂(PPh₃)₃ and Ru(OAc)₂(PPh₃)₂ are commerciallyavailable.

According to a preferred embodiment, the present disclosure may refer toa process to obtain a complex of formula (VI) wherein M is Ru and X═Y═Clor acetate (OAc), by reacting RuCl₂(CO)(PPh₃)₂(dmf) orRu(OAc)₂(CO)(PPh₃)₂ with a phosphine (P) selected among:

-   -   a phosphine of formula PR¹⁶R¹⁷R¹⁸, wherein R¹⁶-R¹⁸ are        independently selected among H, C1-C20 aliphatic group and        C5-C20 aromatic groups; and an optically active phosphine        selected among (S)-neomenthyldiphenylphosphine and        (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl;        and at least one nitrogen-containing compound NN selected among

wherein

-   R¹-R⁶ are independently selected among H, C1-C20 aliphatic group and    C5-C20 aromatic group, preferably R¹ and R² may be independently    selected among H and a phenyl group and/or R³-R⁶ may be H.

According to a further embodiment, the present disclosure may refer to aprocess to obtain complexes of formula (VI) with the limitationsdescribed above.

Non limiting examples of preferred complexes of formula (VI) are:

The synthesis of the monocarbonyl complexes 1-3 involves the use oft,t,t-RuCl₂(CO)(dmf)(PPh₃)₂ as starting product which can be prepared byreaction between the commercially available compound RuCl₂(PPh₃)₃ withCO in dimethylformamide (dmf). The complex 1 was obtained by reactingRuCl₂(CO)(dmf)(PPh₃)₂ with PCy₃ via the mixed phosphine intermediateRuCl₂(CO)(dmf)(PPh₃)(PCy₃) in CH₂Cl₂ and further addition ofethylenediamine, whereas reaction with 2-(aminomethyl)pyridine, in placeof ethylenediamine, gave complex 2. Similarly, complex 3 was preparedusing PiPr₃, in place of PCy₃, with ethylenediamine.

Similarly the complexes 4-7 of the invention were prepared fromRu(OAc)₂(CO)(PPh₃)₂ as starting product, which can be easily prepared ongram-scale by reaction between Ru(OAc)₂(PPh₃)₂ with CO in MeOH. Thecomplexes 4 and 5 were obtained as a mixture by reactingRu(OAc)₂(CO)(PPh₃)₂ with the ligand ethylenediamine in CH₂Cl₂, whereasreaction with 2-(aminomethyl)pyridine, in place of ethylenediamine, gavecomplexes 6 and 7 in a similar ratio of isomer (about 2/3, in favour ofthe cis-OAc isomers).

The activity in transfer hydrogenation of complex 2 is higher than thatof complexes known in the art, such as RuCl₂(CO)(ampy)(PPh₃), reportedby Cavarzan et al. (Polyhedron 2013, 62, 75), since the presence of themore basic phosphine allows the reduction at lower catalyst loading (S/C5000 vs. 500).

According to an embodiment, the present disclosure may refer to acomplex of formula (VII)

[MX(CO)(NN)(PP)]W   (VII)

wherein M, X, W, (NN) and (PP) are as defined above and provided thatwhen X is Cl or H, (NN) is not ethylenediamine or2-(aminomethyl)pyridine and the diphosphine (PP) is notPh₂P(CH₂CH₂CH₂)PPh₂.

According to a specific embodiment, the present disclosure may refer tocomplexes of formula (VII) wherein M, X, and (NN) are as defined above,provided that when X is Cl or H, the diphosphine (PP) may be selectedamong:

-   ferrocene optionally substituted with C1-C20 aliphatic groups;-   an optically active diphosphine selected from the group consisting    of (R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine],    (R)-(1,1′-binaphthalene-2,2′-diyl)bis(diphenylphosphine),    (R)-(1,1′-binaphthalene-2,2′-diyl)bis[bis(3,5-dimethylmethyl)phosphine],    (R)-1-{-2-[diphenylphosphine]ferrocenyl}ethyldicyclohexyl phosphine,    (R)-1-{-2-[bis(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocenyl}ethyldicyclohexyl    phosphine and (2R,4R)-2,4-bis(diphenylphosphine)pentane.

The present disclosure also refers to a process to obtain complexes offormula (VII) comprising reacting [MXY(CO)₂]_(n), MXY(CO)(PPh₃)₂orMXY(CO)(PPh₃)₂(dmf), wherein M, X and Y are as defined above and (dmf)is dimethylformamide, with a diphosphine (PP) selected among:

-   -   a diphosphine of formula P(R¹⁹)₂—Z—P(R²⁰)₂, wherein Z is a C2-C4        aliphatic group or ferrocene, optionally substituted with C1-C20        aliphatic groups, and wherein R¹⁹ and R²⁰ are independently        selected among C1-C20 aliphatic groups and C5-C20 aromatic        groups; and    -   an optically active diphosphine selected from the group        consisting of        (R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine],        (R)-(1,1′-binaphthalene-2,2′-diyl)bis(diphenylphosphine),        (R)-(1,1′-binaphthalene-2,2′-diyl)bis[bis(3,5-dimethylmethyl)phosphine],        (R)-1-{-2-[diphenylphosphine]ferrocenyl}ethyldicyclohexyl        phosphine,        (R)-1-{-2-[bis(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocenyl}ethyldicyclohexyl        phosphine and (2R,4R)-2,4-bis(diphenylphosphine)pentane;        and at least one nitrogen-containing compound NN selected among:

wherein

-   R¹-R⁶ are independently selected among H, C1-C20 aliphatic group and    C5-C20 aromatic group, preferably R¹ and R² may be independently    selected among H and a phenyl group and/or R³-R⁶ may be H.

According to a preferred embodiment, the present disclosure may refer toa process to obtain a complex of formula (VII) wherein M is Ru andX═Y═Cl or acetate (OAc), by reacting [RuCl₂(CO)₂]_(n) orRuCl₂(CO)(PPh₃)₂(dmf) or Ru(OAc)₂(CO)(PPh₃)₂ with a diphosphine (PP)selected among:

-   -   a diphosphine of formula P(R¹⁹)₂—Z—P(R²⁰)₂, wherein Z is a C2-C4        aliphatic group or ferrocene, optionally substituted with C1-C20        aliphatic groups, wherein R¹⁹ and R²⁰ are independently selected        among C1-C20 aliphatic groups and C5-C20 aromatic groups; and    -   an optically active diphosphine selected from the group        consisting of        (R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine],        (R)-(1,1′-binaphthalene-2,2′-diyl)bis(diphenylphosphine),        (R)-(1,1′-binaphthalene-2,2′-diyl)bis[bis(3,5-dimethylmethyl)phosphine],        (R)-1-{-2-[diphenylphosphine]ferrocenyl}ethyldicyclohexyl        phosphine,        (R)-1-{-2-[bis(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocenyl}ethyldicyclohexyl        phosphine and (2R,4R)-2,4-bis(diphenylphosphine)pentane;        and at least one nitrogen-containing compound NN selected among:

wherein

-   R¹-R⁶ are independently selected among H, C1-C20 aliphatic group and    C5-C20 aromatic group, preferably R¹ and R² may be independently    selected among H and a phenyl group and/or R³-R⁶ may be H.

According to a further embodiment, the present disclosure may refer to aprocess to obtain complexes of formula (VII) with the limitationsdescribed above.

The synthetic route described above gives access to several diphosphinederivatives, including derivatives of achiral and chiral diphosphineligands.

Non limiting examples of preferred complexes of formula (VII) are:

The cationic monocarbonyl derivatives 8 and 9 were obtained either fromthe polymer [RuCl₂(CO)₂]_(n), synthesized by reaction of RuCl₃.2.5H₂Owith formic acid or from the complex RuCl₂(CO)(dmf)(PPh₃)₂. Reaction of[RuCl₂(CO)₂]_(n) with 1,4-bis(diphenylphosphino) butane andethylenediamine in 2-propanol led to 8, whereas using1,1′-bis(diphenylphosphino) ferrocene, in place of1,4-bis(diphenylphosphino) butane, gave 9. Reaction ofRuCl₂(CO)(dmf)(PPh₃)₂ takes place in CH₂Cl₂ and affords the sameproducts.

The cationic monocarbonyl derivatives 10-15 were obtained from thecomplex Ru(OAc)₂(CO)(PPh₃)₂ as starting product. The complex 10 wasobtained by a one-pot reaction of Ru(OAc)₂(CO)(PPh₃)₂ with the ligands1,4-bis(diphenylphosphino)butane and ethylenediamine in CH₂Cl_(2.) Thecomplex 11 was obtained, in a similar manner, by using2-(aminomethyl)pyridine in place of ethylenediamine. The complexes 12and 13 were obtained using the ligand1,1′-bis(diphenylphosphino)ferrocene in place of1,4-bis(diphenylphosphino)butane and the ligands ethylenediamine and2-(aminomethyl)pyridine, respectively.

Similarly the complexes 14 and 15 were obtained from the diphosphine(R)-1-[(S_(P))-2-(diphenylphosphino)ferrocenylethyl]diphenylphosphineand the ligands (1R,2R)-1,2-diphenylethylenediamine and(1S,2S)-1,2-diphenylethylenediamine.

The ligands of the type HCNN (IIa-b) have the ability to act both asbidentate (IIa-b) or tridentate ligands of the type (IIc-d) whendeprotonated.

According to an embodiment, in the case of bidentate ligand thecoordination occurs through the nitrogen atom of the —NH₂ group and asecond nitrogen atom of the heterocycle, in combination with amonophosphine to the metal. Thus, the present disclosure may refer to acomplex of formula (VIII)

MXY(CO)(HCNN)(P)   (VIII)

wherein M, X, Y, (HCNN) and (P) are as defined above.

Preferably, the monodentate phosphine (P) is a phosphine of formulaPR¹⁶R¹⁷R¹⁸, wherein R¹⁶-R¹⁸ are independently selected among H, C1-C20aliphatic groups and C5-C20 aromatic groups.

The present disclosure also refers to a process to obtain complexes offormula (VIII) comprising reacting a compound of formula MXY(CO)(PPh₃)₂,or of formula MXY(CO)(PPh₃)₂(dmf), wherein M, X, Y are as defined aboveand (dmf) is dimethylformamide, with a nitrogen-containing compound HCNNselected among:

wherein

-   R⁷-R¹³ are independently selected among H, C1-C20 aliphatic groups,    and C5-C20 aromatic groups, preferably R⁸-R¹³ may be H and/or R⁷ may    be 4-methyl, and optionally with a phosphine (P) selected among:-   a phosphine of formula PR¹⁶R¹⁷R¹⁸, wherein R¹⁶-R¹⁸ are independently    selected among H, C1-C20 aliphatic groups and C5-C20 aromatic    groups; and-   an optically active phosphine selected among    (S)-neomenthyldiphenylphosphine and    (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl.

According to a preferred embodiment, the present disclosure may refer toa process to obtain a complex of formula (VIII) wherein M is Ru andX═Y═Cl or acetate (OAc) and P═PPh₃ by reacting RuCl₂(CO)(PPh₃)₂(dmf) orRu(OAc)₂(CO)(PPh₃)₂ with a nitrogen-containing compound HCNN selectedamong:

wherein

-   R⁷-R¹³ are independently selected among H, C1-C20 aliphatic group    and C5-C20 aromatic group, preferably R⁸-R¹³ may be H and/or R⁷ may    be 4-methyl. Examples of preferred complexes of formula (VIII) are:

The monocarbonyl phosphine derivatives 16-18 were isolated fromRuCl₂(CO)(PPh₃)₂(dmf) and 6-(4-methylphenyl)-2-(aminomethyl)pyridine,2-(aminomethyl)benzo[h]quinoline and 4-phenyl-2-(aminomethyl)benzo[h]quinoline in CHCl₃.

The neutral acetate monocarbonyl triphenylphosphine derivative 19 wasobtained by reacting Ru(OAc)₂(CO)(PPh₃)₂ and6-(4-methylphenyl)-2-(aminomethyl)pyridine in toluene.

Known complexes such as RuCl₂(CO)(ampy)(PPh₃) (Cavarzan et al.,Polyhedron 2013, 62, 75) shows remarkably lower activity and require ahigher catalyst loading compared to compound 16 in transferhydrogenation. The presence of the aromatic ring in the 6 position orthe presence of a benzoquinoline ring lead to catalysts with aremarkably higher activity with respect to those containing the simple2-(aminomethyl)pyridine ligand on account of the cyclometalation whichoccurs in the catalysis.

The HCNN ligands of the type (IIa), which contain a pyridine ringfunctionalized in the 6 position with an aromatic group, and those ofthe type (IIb), containing the benzo[h]quinoline system, have theability to act as anionic tridentate ligands (IIc-d) through thenitrogen atom of the —NH₂ group, a second nitrogen atom of theheterocycle and a cyclometalated carbon atom with the metal. Thus,according to a further embodiment, the present disclosure may refer tocomplexes of formula (IX)

MX(CO)(CNN)(P)   (IX)

wherein M, X, (CNN) and (P) are as defined above.

The present disclosure also refers to a process to obtain complexes offormula (IX) by

-   (i) reacting a compound of formula MXY(PPh₃)₃, wherein M, X and Y    are as described above, with a nitrogen-containing ligand (CNN) of    formula (IIc) or (IId)

wherein

-   R⁷-R¹³ are independently selected among H, C1-C20 aliphatic group    and C5-C20 aromatic group, preferably R⁸-R¹³ may be H and/or R⁷ may    be 4-methyl, and optionally a phosphine (P) selected among:-   a phosphine of formula PR¹⁶R¹⁷R¹⁸, wherein R¹⁶-R¹⁸ are independently    selected among H, C1-C20 aliphatic groups and C5-C20 aromatic    groups;-   an optically active phosphine selected among    (S)-neomenthyldiphenylphosphine and    (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl, thereby    obtaining an intermediate derivative and-   (ii) reacting said derivative with CO.

According to a preferred embodiment, the present disclosure may refer toa process to obtain a complex of formula (IX) wherein M is Ru, X═Y═Cland P═PPh₃ by reacting RuCl(CNN)(PPh₃)₂ with CO where CNN is anitrogen-containing ligand CNN selected among

wherein

-   R⁷-R¹³ are independently selected among H, C1-C20 aliphatic group    and C5-C20 aromatic group, preferably R⁸-R¹³ may be H and/or R⁷ may    be 4-methyl.

RuCl(CNN)(PPh₃)₂ can be prepared according to processes known in theart, for example as described in WO2009/007443.

Non limiting examples of preferred complexes of formula (IX) are:

The monocarbonyl complexes 20-22 were obtained from the diphosphinepincer precursors RuCl(CNN)(PPh₃)₂ (CNN=amtp, ambq and ambq^(Ph)) byreaction with CO in CH₂Cl₂.

The anionic bidentate ligands of the type (IVb), obtained bydeprotonation of an ortho-methyl group, have the ability through P and Catoms, in combination with a NN ligand, to coordinate ruthenium orosmium. Therefore, according to an embodiment, the present disclosuremay refer to the complex of formula (X)

MX(CO)(NN)(CP)   (X)

wherein M, X, (NN) and (CP) are as defined above, with the proviso thatwhen X is Cl, (NN) is not ethylenediamine or 2-(aminomethyl)pyridine and(CP) is not a compound of formula (IVb) in which R²¹═R²²=phenyl andR²³=methyl.

According to an embodiment, R²³ may be —CH₃ and/or R²¹-R²² may be C6-C20cycloaliphatic group or C6-C20 aromatic group, more preferably R²³ maybe —CH₃ and/or R²¹-R²² may be independently selected among phenyl andcyclohexyl group.

According to a further embodiment, the present disclosure may refer to acomplex of formula (X) wherein M, X, (NN) and (CP) are as defined above,with the proviso that when X is Cl, R²¹ and R²² are not aromatic groups.

According to a further embodiment, the present disclosure may refer to acomplex of formula (X) in which M, X, (NN) are as defined above, (CP) isa ligand of formula (IVb)

wherein

R²¹-R²³ are independently selected among H, C1-C20 aliphatic groups andC5-C20 aromatic groups, preferably R²³ may be —CH₃ and/or R²¹-R²² may beC6-C20 cycloaliphatic group or C6-C20 aromatic group, more preferablyR²³ may be —CH₃ and/or R21-R22 may be independently selected amongphenyl and cyclohexyl group; with the proviso that when X is Cl, R²¹ andR²² are not aromatic groups.

The present disclosure refers also to a process to obtain complexes offormula (X) comprising:

-   (i) reacting MX₃.xH₂O with a HCP compound of formula (IVa)

wherein

-   M and X are as defined above and R²¹-R²³ are independently selected    among H, C1-C20 aliphatic groups and C5-C20 aromatic groups, thereby    obtaining an intermediate complex of formula (XI); and-   (ii) reacting the complex of formula (XI) with a (NN) ligand of    formula Ia to Ic:

wherein

-   R¹-R⁶ are independently selected among H, C1-C20 aliphatic group and    C5-C20 aromatic group, preferably R¹ and R² may be independently    selected among H and a phenyl group and/or R³-R⁶ may be H.

According to a preferred embodiment, the present disclosure may refer toa process to obtain a complex of formula (X) wherein M is Ru and X isCl, comprising: (i) reacting RuCl₃.xH₂O with a HCP compound of formula(IVa)

wherein

-   R²¹-R²³ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups, thereby obtaining an intermediate    complex of formula (XI); and (ii) reacting the complex of    formula (XI) with a (NN) ligand of formula (Ia-Ic):

wherein

-   R¹-R⁶ are independently selected among H, C1-C20 aliphatic group and    C5-C20 aromatic group, preferably R¹ and R² may be independently    selected among H and a phenyl group and/or R³-R⁶ may be H.

According to a further embodiment, the present disclosure may refer to aprocess to obtain complexes of formula (X) with the limitationsdescribed above.

Non limiting examples of preferred complexes of formula (X) are:

Complexes 23, 24 were synthesized from 25 by reaction withethylenediamine or 2-(aminomethyl)pyridine, respectively, viadisplacement of the phosphine.

According to a further embodiment, the present disclosure may refer to acomplex of formula (XI)

MX(CO)(CP)(HCP)   (XI)

wherein M, X, (CP) and (HCP) are as defined above and with the provisothat when X is Cl and R²³ is —CH₃, R²¹ and R²² are not phenyl groups.According to an embodiment, R²³ may be —CH₃ and/or R²¹-R²² may be C6-C20cycloaliphatic group or C6-C20 aromatic group, preferably R²¹-R²² may becyclohexyl groups.

According to a specific embodiment, the present disclosure may refer tocomplexes of formula (XI) wherein M, X, (CP) and (HCP) are as definedabove, with the proviso that when X is Cl, R²¹ and R²² are not anaromatic groups.

The complex of formula (XI) is a pentacoordinate complex.

The present disclosure also refers to a process to obtain complexes offormula (XI) comprising reacting MX₃.xH₂O with a HCP compound of formula(IVa)

wherein

-   M and X are as defined above and R²¹-R²³ are independently selected    among H, C1-C20 aliphatic groups and C5-C20 aromatic groups, R²³ may    be —CH₃ and/or R²¹-R²² may be C6-C20 cycloaliphatic group or C6-C20    aromatic group, preferably R²¹-R²² may be cyclohexyl groups.

According to a preferred embodiment, the present disclosure may refer toa process to obtain complexes of formula (XI) in which M is Ru and X isCl by reacting RuCl₃.xH₂O with a HCP compound of formula (IVa)

wherein

-   R²¹-R²³ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups, R²³ may be —CH₃ and/or R²¹-R²² may be    C6-C20 cycloaliphatic group or C6-C20 aromatic group, preferably    R²¹-R²² may be cyclohexyl groups.

According to an embodiment, the present disclosure may refer to aprocess to prepare complexes of formula (XI) with the limitationsdescribed above. Non limiting examples of preferred complexes of formula(XI) is:

The complexes of formula (XI) may be synthesized using the anionicbidentate ligands of the type (IVb), obtained by deprotonation of anortho-methyl group, which have the ability through P and C atoms, tocoordinate ruthenium and osmium.

The cyclometallated monocarbonyl derivatives 25 was prepared by reactionof RuCl₃.xH₂O with (2,6-dimethylphenyl)dicyclohexylphosphine in ethanoland the presence of formaldehyde and triethylamine.

According to an embodiment, the present disclosure may refer tocomplexes of formula (XII)

MXY(CO)(PP)(P)   (XII)

wherein M, X, Y, (PP) and (P) are as defined above. Preferably, (P) istriphenylphosphine.

The present disclosure also refers to a process to obtain the complexesof formula (XII) comprising reacting a compound of formulaMXY(CO)(PPh₃)₂, or of formula MXY(CO)(PPh₃)₂(dmf), wherein M, X, Y areas defined above and (dmf) is dimethylformamide, with a phosphine (P)selected among:

-   -   a phosphine of formula PR¹⁶R¹⁷R¹⁸, wherein R¹⁶-R¹⁸ are        independently selected among H, C1-C20 aliphatic group and        C5-C20 aromatic groups;    -   an optically active phosphine selected among        (S)-neomenthyldiphenylphosphine and        (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl;        and a diphosphine (PP) selected among:    -   a diphosphine of formula P(R¹⁹)₂—Z—P(R²⁰)₂, wherein Z is a C2-C4        aliphatic group or ferrocene optionally substituted with C1-C20        aliphatic groups, and wherein R¹⁹ and R²⁰ are independently        selected among C1-C20 aliphatic groups and C5-C20 aromatic        groups;

an optically active diphosphine selected from the group consisting of(R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine],(R)-(1,1′-binaphthalene-2,2′-diyl)bis(diphenylphosphine),(R)-(1,1′-binaphthalene-2,2′-diyl)bis[bis(3,5-dimethylmethyl)phosphine],(R)-1-{-2-[diphenylphosphine]ferrocenyl}ethyldicyclohexyl phosphine,(R)-1-{-2-[bis(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocenyl}ethyldicyclohexylphosphine and (2R,4R)-2,4-bis(diphenylphosphine)pentane.

According to a preferred embodiment, the present disclosure refers to aprocess to obtain a complex of formula (XII) in which M is Ru and X isCl or acetate group (OAc), by reacting RuCl₂(CO)(PPh₃)₂(dmf) orRu(OAc)₂(CO)(PPh₃)₂ with a phosphine (P) selected among:

-   -   a phosphine of formula PR¹⁶R¹⁷R¹⁸, wherein R¹⁶-R¹⁸ are        independently selected among H, C1-C20 aliphatic group and        C5-C20 aromatic groups;    -   an optically active phosphine selected among        (S)-neomenthyldiphenylphosphine and        (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl;        and a diphosphine (PP) selected among:    -   a diphosphine of formula P(R¹⁹)₂—Z—P(R²⁰)₂, wherein Z is a C2-C4        aliphatic group or ferrocene optionally substituted with C1-C20        aliphatic groups, and wherein R¹⁹ and R²⁰ are independently        selected among C1-C20 aliphatic groups and C5-C20 aromatic        groups;

an optically active diphosphine selected from the group consisting of(R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine],(R)-(1,1′-binaphthalene-2,2′-diyl)bis(diphenylphosphine),(R)-(1,1′-binaphthalene-2,2′-diyl)bis[bis(3,5-dimethylmethyl)phosphine],(R)-1-{-2-[diphenylphosphine]ferrocenyl}ethyldicyclohexyl phosphine,(R)-1-{-2-[bis(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocenyl}ethyldicyclohexylphosphine and (2R,4R)-2,4-bis(diphenylphosphine)pentane.

Non limiting examples of preferred complexes of formula (XII) are:

Complexes 26-36 have been synthesized by substitution of one or twotriphenylphosphine from RuCl₂(CO)(PPh₃)₂(dmf) or Ru(OAc)₂(CO)(PPh₃)₂. Ina further embodiment, the present disclosure may refer to a complex offormula (XIII)

MXY(CO)(HCN)(PP)   (XIII)

wherein M, X, Y, (HCN) and (PP) are as defined above.

-   Preferably, the diphosphine (PP) is selected among a diphosphine of    formula P(R¹⁹)₂—Z—P(R²⁰)₂, wherein Z is a C2-C4 aliphatic group or    ferrocene optionally substituted with C1-C20 aliphatic groups, and    wherein R¹⁹ and R²° are independently selected among C1-C20    aliphatic groups and C5-C20 aromatic groups.

The present disclosure also refers to a process to obtain a complex offormula (XIII) comprising reacting a compound of formula MXY(CO)(PPh₃)₂,or of formula MXY(CO)(PPh₃)₂(dmf), wherein M, X, Y are as defined aboveand (dmf) is dimethylformamide, with a diphosphine (PP) selected among:

-   a diphosphine of formula P(R¹⁹)₂—Z—P(R²⁰)₂, wherein Z is a C2-C4    aliphatic group or ferrocene optionally substituted with C1-C20    aliphatic groups, and wherein R¹⁹ and R²⁰ are independently selected    among C1-C20 aliphatic groups and C5-C20 aromatic groups;-   an optically active diphosphine selected from the group consisting    of (R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine],    (R)-(1,1′-binaphthalene-2,2′-diyl)bis(diphenylphosphine),    (R)-(1,1′-binaphthalene-2,2′-diyl)bis[bis(3,5-dimethylmethyl)phosphine],    (R)-1-{-2-[diphenylphosphine]ferrocenyl}ethyldicyclohexyl phosphine,    (R)-1-{-2-[bis(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocenyl}ethyldicyclohexyl    phosphine and (2R,4R)-2,4-bis(diphenylphosphine)pentane;-   and a nitrogen-containing ligand (HCN) of formula IIIa

wherein

-   R¹⁴ and R¹⁵ are independently selected among H, C1-C20 aliphatic    groups and C5-C20 aromatic groups, preferably R¹⁴ and R¹⁵ may be    independently H.

According to a specific embodiment, the present disclosure refers to aprocess to obtain a complex of formula (XIII) in which M is Ru and X isCl or acetate group, by reacting a compound of formulaRuCl₂(CO)(PPh₃)₂(dmf) or Ru(OAc)₂(CO)(PPh₃)₂ with a phosphine (PP)selected among:

-   -   a diphosphine of formula P(R¹⁹)₂—Z—P(R²⁰)₂, wherein Z is a C2-C4        aliphatic group or ferrocene optionally substituted with C1-C20        aliphatic groups, and wherein R¹⁹ and R²⁰ are independently        selected among C1-C20 aliphatic groups and C5-C20 aromatic        groups;

-   an optically active diphosphine selected from the group consisting    of (R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine],    (R)-(1,1′-binaphthalene-2,2′-diyl)bis(diphenylphosphine),    (R)-(1,1′-binaphthalene-2,2′-diyl)bis[bis(3,5-dimethylmethyl)phosphine],    (R)-1-{-2-[diphenylphosphine]ferrocenyl}ethyldicyclohexyl phosphine,    (R)-1-{-2-[bis(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocenyl}ethyldicyclohexyl    phosphine and (2R,4R)-2,4-bis(diphenylphosphine)pentane;    and a nitrogen-containing ligand (HCN) of formula IIIa

wherein

-   R¹-R¹⁵ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups, preferably R¹⁴ and R¹⁵ may be    independently H.

Non limiting examples of preferred complexes of formula (XIII) are:

In a further embodiment, the present disclosure may refer to a complexof formula (XIV)

MXY(CO)(PNN)   (XIV)

wherein M, X, Y and (PNN) are as defined above.

According to a specific embodiment, the present disclosure may refer tocomplexes of formula (XIV) wherein M, X, Y and (PNN) are as definedabove, provided that when X═Y, X and Y are not Cl.

The present disclosure also refers to a method to obtain the complexesof formula (XIV) comprising reacting a compound of formulaMXY(CO)(PPh₃)₂, or of formula MXY(CO)(PPh₃)₂(dmf), wherein M, X, Y areas defined above and (dmf) is dimethylformamide with a tridentate (PNN)ligand of formula (V)

wherein

-   R²⁴-R²⁹ are independently selected among H, C1-C20 alkyl group and    C5-C20 aryl groups, preferably R²⁴ and R²⁷-R²⁹ may be H and/or R²⁵    and R²⁶ may be a C1-C20 aromatic group, more preferably a phenyl    group.

According to a specific embodiment, the present disclosure may refer toa process to obtain a complex of formula (XIV) in which M is Ru and X isacetate group comprising reacting a compound of formulaRu(OAc)₂(CO)(PPh₃)₂ with a tridentate (PNN) ligand of formula (V)

wherein

-   R²⁴-R²⁹ are independently selected among H, C1-C20 alkyl groups and    C5-C20 aryl groups, preferably R²⁴ and R²⁷-R²⁹ may be H and/or R²⁵    and R²⁶ may be a C1-C20 aromatic group, more preferably a phenyl    group.

According to a further embodiment, the present disclosure may refer to aprocess to obtain a complex of formula (XIV) with the limitationsdescribed above.

A non-limiting example of complexes of formula (XIV) is:

Complexes of formula (1) and sub-formulas (VI-XIV) have been found to behighly active in transfer hydrogenation of ketones and aldehydes and canbe used in hydrogenation of the same compounds using molecular hydrogen.

A further aspect of the present disclosure is the use of the complex offormula (1) or of sub-formulas (VI-XIV) as catalysts or pre-catalyst forthe reduction reaction of ketones or aldehydes to alcohols by transferhydrogenation or hydrogenation with molecular hydrogen.

In another aspect, the present disclosure refers to a process for thereduction of ketones or aldehydes to the corresponding alcoholscomprising the following steps:

-   (a) mixing a catalyst or pre-catalyst with a solution comprising at    least one base and at least one substrate selected from the group    consisting of C3-C42 ketones and C2-C41 aldehydes thereby obtaining    a mixture; and-   (b) contacting said mixture with molecular H₂ or with at least one    hydrogen-donor, preferably 2-propanol, sodium formate, ammonium    formate, a mixture of formic acid and triethylamine,    said process being characterized in that the catalyst or    pre-catalyst is a pentacoordinate or a hexacoordinate complex of    general formula (1):

[MXY_(a)(CO)L_(b)L′_(c)]W_(d)   (1)

wherein

-   M=Ru or Os;-   a, b and d are independently 0 or 1;-   c is 1 or 2;-   X, Y are independently selected among halides, hydride, C1-C20    carboxylates and C1-C20 alkoxides;-   W is selected among halides, C1-C20 carboxylates and C1-C20    alkoxides;-   L is a nitrogen-containing ligand selected among:-   (I) a NN compound of formula Ia to Ic:

(II) a HCNN compound of formula IIa-IIb and a CNN ligand of formulaIIc-IId:

(III) a HCN compound of formula IIIa

wherein

-   R¹-R¹⁵ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups, preferably R¹ and R² may be    independently selected among H and a phenyl group and/or R³-R⁶ and    R⁸-R¹⁵ may be H and/or R⁷ may be 4-methyl;-   L′ is at least one phosphorus-containing ligand selected among:-   a phosphine (P) selected among: a phosphine of formula PR¹⁶R¹⁷R¹⁸,    wherein R16-R¹⁸ are independently selected among H, C1-C20 aliphatic    groups and C5-C20 aromatic groups; an optically active phosphine    selected among (S)-neomenthyldiphenylphosphine and    (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl;-   a diphosphine (PP) selected among: a diphosphine of formula    P(R¹⁹)₂—Z—P(R²⁰)₂, wherein Z is a C2-C4 aliphatic group or ferrocene    optionally substituted with C1-C20 aliphatic groups, and wherein R¹⁹    and R²⁰ are independently selected among C1-C20 aliphatic groups and    C5-C20 aromatic groups; an optically active diphosphine selected    from the group consisting of    (R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine],    (R)-(1,1′-binaphthalene-2,2′-diyl)bis(diphenylphosphine),    (R)-(1,1′-binaphthalene-2,2′-diyl)bis[bis(3,5-dimethylmethyl)phosphine],    (R)-1-{-2-[diphenylphosphine]ferrocenyl}ethyldicyclohexyl phosphine,    (R)-1-{-2-[bis(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocenyl}ethyldicyclohexyl    phosphine and (2R,4R)-2,4-bis(diphenylphosphine)pentane;-   a HCP compound of formula (IVa) and a CP ligand of formula (IVb)

wherein

-   R²¹-R²³ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups, R²³ may be —CH₃ and/or R²¹-R²² may be    C6-C20 cycloaliphatic group or C6-C20 aromatic group, preferably    R²¹-R²² may be cyclohexyl groups;-   a PNN compound of formula (V)

wherein

-   R²⁴-R²⁹ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups, preferably R²⁴ and R²⁷-R²⁹ may be H    and/or R²⁵ and R²⁶ may be a C1-C20 aromatic group, more preferably a    phenyl group.

According to a further embodiment, the present disclosure may refer to aprocess for the reduction of ketones or aldehydes to the correspondingalcohols, wherein the catalyst or pre-catalyst is a pentacoordinate or ahexacoordinate complex of general formula (1) with at least one of thelimitations described above.

The complex of formula (1) containing only phosphorus-containing ligandsL′ is conveniently used as pre-catalyst in transfer hydrogenation orhydrogenation with molecular hydrogen, wherein the(transfer)hydrogenation is carried out in the presence of anitrogen-containing ligand L.

Therefore, according to an embodiment, the present disclosure refers toa process for the reduction of ketones or aldehydes to the correspondingalcohols, comprising the following steps:

-   (a) mixing a pre-catalyst with a solution comprising at least one    base and at least one substrate selected from the group consisting    of C3-C42 ketones and C2-C41 aldehydes thereby obtaining a mixture;    and-   (b) contacting said mixture with molecular H₂ or with at least one    hydrogen-donor, preferably 2-propanol, sodium formate, ammonium    formate, a mixture of formic acid and triethylamine,-   wherein said pre-catalyst has general formula (2):

[MXY_(a)(CO)L′_(c)]W_(d)   (2)

wherein

-   M=Ru or Os;-   a, b and d are independently 0 or 1;-   c is 1 or 2;-   X, Y are independently selected among halides, hydride, C1-C20    carboxylates and C1-C20 alkoxides;-   W is selected among halides, C1-C20 carboxylates and C1-C20    alkoxides;-   L′ is at least one phosphorus-containing ligand selected among:-   a phosphine (P) selected among: a phosphine of formula PR¹⁶R¹⁷R¹⁸,    wherein R¹⁶-R¹⁸ are independently selected among H, C1-C20 aliphatic    groups and C5-C20 aromatic groups; an optically active phosphine    selected among (S)-neomenthyldiphenylphosphine and    (R)-(+)-2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl;-   a diphosphine (PP) selected among: a diphosphine of formula    P(R¹⁹)₂—Z—P(R²⁰)₂, wherein Z is a C2-C4 aliphatic group or ferrocene    optionally substituted with C1-C20 aliphatic groups, and wherein R¹⁹    and R²° are independently selected among C1-C20 aliphatic groups and    C5-C20 aromatic groups; an optically active diphosphine selected    from the group consisting of    (R)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diphenylphosphine],    (R)-(1,1′-binaphthalene-2,2′-diyl)bis(diphenylphosphine),    (R)-(1,1′-binaphthalene-2,2′-diyl)bis[bis(3,5-dimethylmethyl)phosphine],    (R)-1-{-2-[diphenylphosphine]ferrocenyl}ethyldicyclohexyl phosphine,    (R)-1-{-2-[bis(3,5-dimethyl-4-methoxyphenyl)phosphine]ferrocenyl}ethyldicyclohexyl    phosphine and (2R,4R)-2,4-bis(diphenylphosphine)pentane;-   a HCP compound of formula (IVa) and a CP ligand of formula (IVb)

wherein

-   R²¹-R²³ are independently selected among H, C1-C20 aliphatic groups    and C5-C20 aromatic groups R²³ may be —CH₃ and/or R²¹-R²² may be    C6-C20 cycloaliphatic group or C6-C20 aromatic group, preferably    R²¹-R²² may be cyclohexyl groups-   and wherein-   step (a) is carried out by mixing said pre-catalyst with a solution    further comprising at least one nitrogen-containing compound L    selected among:-   (i) a NN compound of formula Ia to Ic:

(ii) a HCNN compound of formula IIa-IIb and a CNN ligand of formulaIIc-IId:

(iii) a HCN compound of formula IIIa

(iv) a PNN compound of formula (V)

wherein

-   R¹-R¹⁵ and R²⁴-R²⁹ are independently selected among H, C1-C20    aliphatic groups and C5-C20 aromatic groups, preferably R¹ and R²    and R²⁴-R²⁹ may be independently selected among H and a phenyl group    and/or R³-R⁶ and R⁸-R¹⁵ may be H and/or R⁷ may be 4-methyl.

Preferably, the nitrogen-containing compound is selected among NNcompounds of formula (Ia) to (Ic)

wherein R¹-R⁶ are independently selected among H, C1-C20 aliphaticgroups and C5-C20 aromatic groups. More preferably, thenitrogen-containing compound is selected among ethylenediamine and2-(aminomethyl)pyridine.

According to an embodiment, the step (a) of the processes describedabove may be conducted in the presence of a base, wherein said base maybe potassium hydroxide, potassium carbonate or an alkali metal alkoxidepreferably selected among sodium iso-propoxide, potassium tert-butoxide,more preferably is potassium tert-butoxide, and in step (b) the mixtureis contacted with molecular hydrogen.

According to a further embodiment, in the process of the disclosure instep (a) the base is sodium iso-propoxide and in step (b) the mixture iscontacted with at least one hydrogen donor.

The transfer hydrogenation reduction process of the present disclosuremay be carried out at a temperature of 30-82° C.

In one embodiment, the reduction reactions by hydrogenation may becarried out at 40-70° C. under hydrogen atmosphere (5-30 atm) inpresence of methanol or ethanol as solvent. Under these reactionconditions the conversion of the ketone or aldehyde to alcohol is goodto complete.

The complex of the present disclosure can be used for the preparation ofalcohols, also chiral, by the reduction of C3-C41 ketones and of C2-C41aldehydes.

In the process of the disclosure, the substrate may be:

-   at least one C3-C41 ketone selected among compounds of formula    R³⁰C(═O)R³¹ wherein R³⁰ and R³¹ are independently selected among    C1-C20 aliphatic, substituted aliphatic, aromatic, substituted    aromatic and heteroaromatic groups wherein optionally R³⁰ and R³¹    are linked to form a cycle;-   at least one C2-C41 aldehyde is selected among compounds of formula    R³²C(═O)H, wherein R³² is selected among C1-C40 aliphatic,    substituted aliphatic, aromatic, substituted aromatic and    heteroaromatic groups; and-   mixtures thereof.

According to an embodiment, in the process of the present disclosure themolar ratio substrate/catalyst or pre-catalyst may range from 1000/1 to100000/1, preferably from 1000/1 to 50000/1.

According to a further embodiment, in the process of the presentdisclosure the molar ratio substrate/base may range from 10/1 to 100/1.

In a further embodiment, the present disclosure may refer to complexesof formula (1) and (2) and of sub-formulas (VI)-(XIV) as described abovein which M is Ru.

In a further embodiment, the present disclosure may refer to complexesof formula (1) and (2) and of sub-formulas (VI-XIV) as described above,wherein X and Y are equal. More preferably, the present disclosure mayrefer to complexes of formula (1) and (2) and of sub-formulas (VI-XIV)as described above, wherein X and Y are equal and are selected among CIand acetate group.

In a further embodiment, the present disclosure may refer to a complexof formula (1) and (2) and of sub-formula (VII) as described above,wherein W is chlorine.

These and other objects as well as features and advantages of thepresent invention will be better understood from the following detaileddescription and from the preferred embodiments which are given forillustrative purposes and not limitative of the invention itself.

EXAMPLE 1 Synthesis of the Complex RuCl₂(CO)(en)(PCy₃) (1)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (250 mg, 0.31 mmol, 1 equiv),suspended in 5 mL of dichloromethane, was reacted with PCy₃ (176 mg,0.63 mmol, 2 equiv). After stirring the mixture for 3 hours at roomtemperature, the ligand en (25 μL, 0.37 mmol, 1.2 equiv) was added andthe solution was stirred for 3 hours at room temperature. The volume wasreduced to about half and the complex was precipitated by adding 5 mL ofpentane. The obtained solid was filtered, washed 2 times with 10 mL ofethyl ether and dried under reduced pressure. Yield: 149 mg (89%). Anal.Calcd (%) for C₂₁H₄₁Cl₂N₂OPRu: C, 46.66; H, 7.65; N, 5.18, Found: C,46.39; H, 7.49; N, 5,36. ¹H NMR (200 MHz, CD₂Cl₂) δ 3.77-3.62 (m, 2H),3.35-3.20 (m, 2H), 3.09 (dd, J=10.9, 5.5 Hz, 2H), 2.92 (dd, J=9.7, 6.0Hz, 2H), 2.32-1.08 (m, 33H). ¹³C NMR (50 MHz, CD₂Cl₂) δ 206.0 (d, J=16.8Hz), 43.5 (d, J=2.8 Hz), 42.3 (d, J=1.5 Hz), 35.3 (d, J=21.0 Hz), 29.7,28.2 (d, J=10.0 Hz), 27.0. ³¹P NMR (81.0 MHz, CD₂Cl₂) δ 45.5. IR (cm⁻¹):1936.

EXAMPLE 2 Synthesis of the Complex RuCl₂(CO)(ampy)(PCy₃) (2)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (300 mg, 0.38 mmol, 1 equiv),suspended in 5 mL of dichloromethane, was reacted with the ligand PCy₃(210 mg, 0.75 mmol, 2 equiv). After stirring the mixture for 3 hours atroom temperature, the ligand ampy (47 μL, 0.45 mmol, 1.2 equiv) wasadded. The solution was stirred for 3 hours at room temperature, thevolume was reduced to about half and the complex was precipitated byadding 5 mL of pentane. The obtained solid was filtered, washed 2 timeswith 10 mL of ethyl ether and dried under reduced pressure. Yield: 187mg (84%). Anal. Calcd (%) for C₂₅H₄₁Cl₂OPRu: C, 51.02; H, 7.02; N, 4.76,Found: C, 51.26; H, 7.22; N, 4.57. ¹H NMR (200 MHz, CD₂Cl₂) δ 9.11 (d,J=5.5 Hz, 1H), 7.88-7.62 (m, 1H), 7.55-7.28 (m, 1H), 7.28-7.10 (m, 1H),4.70 (t, J=5.9 Hz, 2H), 4.20 (t, J=5.6 Hz, 2H), 2.33 (ddt, J=23.4, 12.1,2,8 Hz, 3H), 2.18-1.06 (m, 30H). ¹³C NMR (50 MHz, CD₂Cl₂) δ 207.5 (d,J=17.8 Hz), 160.1, 152.55, 137.6, 124.4 (d, J=2.2 Hz), 121.7 (d, J=2.0Hz), 50.6 (d, J=2.3 Hz), 34.5 (d, J=21.1 Hz), 29.5, 28.1 (d, J=10.1 Hz),27.0. ³¹P NMR (81.0 MHz, CD₂Cl₂) δ 45.9. IR (cm⁻¹): 1941.

EXAMPLE 3 Synthesis of the Complex RuCl₂(CO)(en)(PiPr₃) (3)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (81.7 mg, 0.10 mmol, 1 equiv),suspended in 5 mL of distilled dichloromethane, was reacted with theligand PiPr₃ (25 μL, 0.13 mmol, 1.3 equiv). After stirring the mixturefor 3 hours at room temperature, the ligand en (11 μL, 0.16 mmol, 1.6equiv) was added. The solution was stirred for 3 hours at roomtemperature. The volume was reduced to about half and the complex wasprecipitated by adding 5 mL of pentane. The obtained solid was filtered,washed 2 times with 10 mL of ethyl ether and dried at reduced pressure.Yield: 28 mg (66%). Anal. Calcd (%) for C₁₂H₂₉Cl₂N₂OPRu: C, 34.29; H,6.95; N, 6.66, Found: C, 34.00; H, 7.20; N, 6.60. ¹H NMR (200 MHz,CD₂Cl₂) δ 3.70-3.51 (m, 2H), 3.39-3.23 (m, 2H), 3.09 (dd, J=11.2, 5.7Hz, 2H), 3.01-2.85 (m, 2H), 2.63-2.39 (m, 3H), 1.33 (dd, J=13.1, 7.3 Hz,18H). ¹³C NMR (50 MHz, CD₂Cl₂) δ 205.8 (d, J=17.0 Hz), 43.5 (d, J=2.9Hz), 42.2 (d, J=1.7 Hz), 25.1 (d, J=22.4 Hz), 19.6 (d, J=0.7 Hz). ³¹PNMR (81.0 MHz, CD₂Cl₂) δ 55.8. IR (cm⁻¹): 1921.

EXAMPLE 4 Synthesis of the Complex Ru(OAc)₂(CO)(en)(PPh₃) (4 and 5)

The complex Ru(OAc)₂(CO)(PPh₃)₂ (150 mg, 0.19 mmol, 1 equiv) suspendedin CH₂Cl₂ (2 mL) was reacted with the ligand en (16 μL, 0.24 mmol, 1.2equiv). After stirring the mixture for 2 h at room temperature, thevolume was reduced to about half and the complex was precipitated byadding 10 mL of n-heptane. The obtained solid was filtered, washed 3times with ethyl ether (3 mL), once with n-pentane (3 mL) and driedunder reduced pressure. Yield: 64 mg (58%) as a mixture of cis and transcomplexes 4 and 5, in 2/3 ratio respectively. Anal. Calcd (%) forC₂₅H₂₉N₂O₅PRu: C, 52.72; H, 5.13; N, 4.92, Found: C, 52.90; H, 5.02; N,5.14. ¹H NMR (200 MHz, CD₂Cl₂) δ 7.92-7.20 (m, 21H), 7.06-6.84 (m,0.4H), 5.28-5.13 (m, 0.4H), 5.04-4.85 (m, 2H), 4.01-3.78 (m, 2H),3.23-3.04 (m, 0.4H), 2.88-2.75 (m, 0.4H), 2.75-2.57 (m, 2.8H), 2.54-2.37(m, 2.8H), 1.98 (s, 1.2H), 1.62 (s, 6H), 1.58 (s, 1.2H). ¹³C NMR (50MHz, CD₂Cl₂) δ 205.1 (d, J=17.9 Hz), 204.7 (d, J=17.9 Hz), 181.6, 180.4,179.4, 134.4 (d, J=1.3 Hz), 134.0 (d, J=10.4 Hz), 133.8 (d, J=10.5 Hz),133.5 (d, J=1.3 Hz), 133.2 (d, J=1.0 Hz), 130.3, 130.3, 128.8 (d, J=3.8Hz), 128.6 (d, J=3.7 Hz), 46.8 (d, J=3.1 Hz), 44.5 (d, J=2.4 Hz), 44.0(d, J=1.9 Hz), 43.4 (d, J=4.1 Hz), 25.3, 24.4, 24.3. ³¹P NMR (81.0 MHz,CD₂Cl₂) δ 51.6, 47.3. IR (cm⁻¹): 1934, 1924.

EXAMPLE 5 Synthesis of the Complex Ru(OAc)₂(CO)(ampy)(PPh₃) (6 and 7)

The complex Ru(OAc)₂(CO)(PPh₃)₂ (150 mg, 0.19 mmol, 1 equiv) suspendedin CH₂Cl₂ (2 mL) was reacted with the ligand Ampy (25 μL, 0.24 mmol, 1.2equiv). After stirring the mixture for 2 h at room temperature, thevolume was reduced to about half and the complex was precipitated byadding 10 mL of n-heptane. The obtained solid was filtered, washed 3times with ethyl ether (3 mL), once with n-pentane (3 mL) and driedunder reduced pressure. Yield: 77 mg (64%) as a mixture of 6 and 7 in a2/3 ratio respectively. Anal. Calcd (%) for C₂₉H₂₉N₂O₅PRu: C, 56.40; H,4.73; N, 4.54, Found: C, 56.75; H, 4.59; N, 4.23. ¹H NMR (200 MHz,CD₂Cl₂) δ 9.49-9.42 (m, 0.7H), 9.10-8.66 (m, 0.7H), 8.59-8.48 (m, 1 H),7.83-7.22 (m, 25H), 5.40 (t, J=5.7 Hz, 1.4H), 4.21 (t, J=6.2 Hz, 1.4),4.08 (dd, J=16.2, 5.0 Hz, 1 H), 3.87 (ddd, J=15.7, 9.8, 5.8 Hz, 1H),2.08 (s, 2.1H), 2.01 (s, 2.1H), 1.43 (s, 3H), 1.33 (s, 3H). ¹³C NMR (50MHz, CD₂Cl₂) δ 205.8 (d, J=17.7 Hz), 205.5 (d, J=18.9 Hz), 182.1, 179.8,177.8, 163.4, 161.3 (d, J=1.8 Hz), 154.7, 150.3, 138.5, 138.0, 134.2 (d,J=10.5 Hz), 134.1 (d, J=10.5 Hz), 133.4, 133.0, 132.5, 130.5 (d, J=2.3Hz), 130.4 (d, J=2.5 Hz), 128.8 (d, J=9.8 Hz), 128.6 (d, J=9.8 Hz),124.2 (d, J=2.8 Hz), 123.6 (d, J=2.4 Hz), 121.2 (d, J=1.8 Hz), 121.0 (d,J=1.4 Hz), 52.9 (d, J=2.3 Hz), 49.5 (d, J=3.5 Hz), 25.0, 24.3, 24.1. ³¹PNMR (81.0 MHz, CD₂Cl₂) δ 53.8, 49.8. IR (cm⁻¹): 1945, 1923.

EXAMPLE 6 Synthesis of the Complex [RuCl(CO)(en)(dppb)]Cl (8)

The complex [RuCl₂(CO)₂]_(n) (50 mg, 0.22 mmol, 1 equiv) suspended in 5mL of distilled isopropanol, was reacted with the ligand dppb (94 mg,0.22 mmol, 1 equiv). After stirring the mixture for 2 hours at 90° C.,the ligand en (15 μL, 0.22 mmol, 1 equiv) was added and stirred forfurther 2 hours at 90° C. The solution was evaporated in vacuum, and thesolid was dissolved in CHCl₃ (3 mL) and stirred for 3 hours at roomtemperature. The volume was reduced by half, the complex wasprecipitated by adding 5 mL of pentane. The obtained solid was filtered,washed 2 times with 10 mL of ethyl ether and dried at reduced pressure.Yield: 151 mg (98%). Anal. Calcd (%) for C₃₂H₃₆ClN₂O₂P₂Ru: C, 56.60; H,5.34; N, 4.13, Found: C, 56.59; H, 5.39; N, 4.20. ¹H NMR (200 MHz,CDCl₃) δ 7.84-7.65 (m, 4H), 7.56-7.29 (m, 16H), 3.68-3.37 (m, 2H),3.05-2.74 (m, 4H), 2.65-2.35 (m, 4H), 2.18-1.87 (m, 2H), 1.76-1.52 (m,4H). ¹³C NMR (50 MHz, CD₂Cl₂) δ 199.5 (t, J=13.6 Hz), 137.1 (t, J=13.8Hz), 135.9 (t, J=13.9 Hz), 134.6 (t, J=5.1 Hz), 131.6 (d, J=3.6 Hz),130.4, 129.3 (t, J=4.6 Hz), 129.0 (t, J=5.0 Hz), 45.9, 25.5 (t, J=13.8Hz), 24.9 (t, J=16.2 Hz), 22.1. ³¹P NMR (81.0 MHz, CD₂Cl₂) δ 37.4. IR(cm⁻¹): 1969.

EXAMPLE 7 Synthesis of the Complex [RuCl(CO)(en)(dppf)]Cl (9)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (200 mg, 0.25 mmol, 1 equiv) dissolvedin CH₂Cl₂ (2 mL) was reacted with the ligand dppf (160 mg, 0.29 mmol,1.2 equiv) at room temperature for 2 h. The ligand en (15 μL, 0.37 mmol,1.5 equiv) was then added and the mixture was stirred at roomtemperature for 2 h. The solution was concentrated to about 0.5 mL andthe complex was precipitated by addition of n-heptane (10 mL). Theobtained solid was filtered and thoroughly washed 4 times with ethylether (3 mL) and dried under reduced pressure. Yield: 180 mg (88%).Anal. Calcd (%) for C₃₇H₃₆Cl₂FeN₂OP₂Ru: C, 54.56; H, 4.46; N, 3.44,Found: C, 54.50; H, 4.51; N, 3.47. ¹H NMR (200 MHz, CD₂Cl₂) δ 7.97-7.24(m, 20H), 5.59 (s, 2H), 5.15-4.91 (m, 2H), 4.53 (s, 2H), 4.20 (s, 2H),3.97 (s, 2H), 3.68-3.42 (m, 2H), 2.58-2.41 (m, 2H), 2.14-1.85 (m, 2H).¹³C NMR (50 MHz, CD₂Cl₂) δ 204.0 (t, J=14.8 Hz), 135.9 (t, J=5.7 Hz),134.2, 134.1 (d, J=10.1 Hz), 133.4, 132.9 (t, J=4.7 Hz), 132.0, 130.7,130.4 (d, J=2.4 Hz), 129.2-128.3 (m), 77.8 (t, J=4.9 Hz), 75.7 (t, J=3.2Hz), 73.5 (t, J=3.3 Hz), 71.3 (t, J=3.0 Hz), 45.7. ³¹P NMR (81.0 MHz,CD₂Cl₂) δ 39.8. IR (cm⁻¹): 1960.

EXAMPLE 8 Synthesis of the Complex [Ru(OAc)(CO)(en)(dppb)]OAc (10)

The complex Ru(OAc)₂(CO)(PPh₃)₂ (200 mg, 0.26 mmol, 1 equiv) suspendedin CH₂Cl₂ (2 mL) was reacted with the ligand dppb (120 mg, 0.29 mmol,1.1 equiv) at room temperature for 6 h. The ligand en (25 μL, 0.37 mmol,1.4 equiv) was added and the solution was stirred at room temperaturefor further 2 h. The solution was concentrated to about 0.5 mL and thecomplex was precipitated by addition of n-heptane (10 mL). The obtainedsolid was filtered and washed 4 times with ethyl ether (3 mL) and driedunder reduced pressure. Yield: 182 mg (97%). Anal. Calcd (%) forC₃₅H₄₂N₂O₅P₂Ru: C, 57.29; H, 5.77; N, 3.82 Found: C, 57.70; H, 5.90; N,3.50. ¹H NMR (200 MHz, CD₃OD) δ 7.64-7.30 (m, 21 H), 4.76-4.62 (m, 1 H),4.30-4.14 (m, 1H), 4.10-3.92 (m, 1H), 2.92-2.47 (m, 6H), 1.86 (s, 3H),1.58 (s, 3H), 1.31-1.18 (m, 2H). ¹³C NMR (50 MHz, CD₃OD) δ 203.8 (t,J=17.7 Hz), 182.7, 182.5, 134.8 (d, J=10.5 Hz), 134.4-134.1 (m),133.8-133.6 (m), 132.3, 131.7, 131.2 (d, J=2.3 Hz), 130.1 (t, J=4.8 Hz),129.8 (t, J=4.8 Hz), 129.4 (d, J=9.7 Hz), 46.6 (d, J=10.6 Hz), 44.7 (d,J=11.0 Hz), 30.1 (d, J=6.7 Hz), 29.6 (d, J=14.2 Hz), 25.5, 24.0,23.5.³¹P NMR (81.0 MHz, CD₃OD) δ 37.1. IR (cm⁻¹): 1939.

EXAMPLE 9 Synthesis of the Complex [Ru(OAc)(CO)(ampy)(dppb)]OAc (11)

In an NMR tube the complex Ru(OAc)₂(CO)(dppb) (32) (31 mg, 0.05 mmol, 1equiv) suspended in 0.6 mL of toluene-d₈, was reacted with the ligandampy (5 μL, 0.05 mmol, 1 equiv). After stirring the mixture at roomtemperature for 30 min, the sample was characterized by NMR. The samplewas then dried under low pressure. Yield: 31.3 mg (87%). Anal. Calcd (%)for C₃₉H₄₂N₂O₅P₂Ru: C, 59.92; H, 5.42; N, 3.58 Found: C, 60.30; H, 5.60;N, 3.20. ¹H NMR (200 MHz, toluene-d₈) δ 8.19-7.94 (m, 4H), 7.61-6.80 (m,17H), 6.68-6.55 (m, 1 H), 6.47 (dd, J=7.0, 5.1 Hz, 1 H), 6.33-6.06 (m, 1H), 4.20 (t, J=17.4 Hz, 1H), 3.20 (t, J=12.0 Hz, 1 H), 3.07-2.86 (m,1H), 2.66-2.42 (m, 1H), 2.03 (s, 3H), 1.93 (s, 3H), 1.84-1.56 (m, 3H),1.48-1.12 (m, 5H). ¹³C NMR (50 MHz, toluene-d₈) δ 203.3, 187.6, 177.0,163.2, 159.8, 149.1 (d, J=22.9 Hz), 135.6, 134.9-132.0 (m), 130.5-129.4(m), 121.3 (d, J=13.4 Hz), 121.3, 120.8, 50.4, 30.7, 30.1, 29.9, 29.4,25.8, 24.6 (d, J=4.2 Hz). ³¹P NMR (81.0 MHz, toluene-d₈) δ 46.4 (d,J=28.8 Hz), 34.0 (d, J=29.0 Hz). IR (cm⁻¹): 1944, 1608, 1586.

EXAMPLE 10 Synthesis of the Complex [Ru(OAc)(CO)(en)(dppf)]OAc (12)

In an NMR tube the complex Ru(OAc)₂(CO)(dppf) (33) (31.9 mg, 0.04 mmol,1 equiv) suspended in 0.6 mL of toluene-d₈, was reacted with the liganden (3 μL, 0.05 mmol, 1.1 equiv). After heating the mixture at 90° C. for3 h, the sample was dried. The residue was dissolved in CD₂Cl₂ andcharacterized by NMR. The sample was then dried under low pressure.Yield: 30.3 mg (88%). Anal. Calcd (%) for C₄₁H₄₂FeN₂O₅P₂Ru: C, 57.15; H,4.91; N, 3.25 Found: C, 57.10; H, 4.50; N, 2.91.¹H NMR (200 MHz, CD₂Cl₂)δ 7.94-7.20 (m, 20H), 4.67-4.04 (m, 8H), 3.08-2.46 (m, 8H), 1.78 (sbroad, 6H). ¹³C NMR (50 MHz, CD₂Cl₂) δ 203.18 (t, J=15.1 Hz), 181.34(s), 176.62 (dd, J=12.1, 5.5 Hz), 134.53 (t, J=5.2 Hz), 134.01 (t, J=5.3Hz), 132.99 (dd, J=16.2, 13.5 Hz), 131.31 (s), 129.15 (t, J=4.9 Hz),128.57 (t, J=4.9 Hz), 79.63 (dd, J=65.8, 9.6 Hz), 75.90 (t, J=4.2 Hz),75.53 (t, J=4.5 Hz), 73.09 (t, J=3.1 Hz), 72.80 (t, J=3.1 Hz), 45.70(s), 26.06 (s). ³¹P NMR (81.0 MHz, CD₂Cl₂) δ 40.1. IR (cm⁻¹): 1963,1617, 1569.

EXAMPLE 11 Synthesis of the Complex [Ru(OAc)(CO)(ampy)(dppf)]OAc (13)

In an NMR tube the complex Ru(OAc)₂(CO)(dppf) (33) (30.4 mg, 0.04 mmol,1 equiv) suspended in 0.6 mL of toluene-d₈, was reacted with the ligandampy (4 μL, 0.04 mmol, 1 equiv). After stirring at room temperature for2 h, the sample was characterized by NMR. The sample was then driedunder low pressure. Yield: 30.1 mg (87%). Anal. Calcd (%) forC₄₅H₄₂FeN₂O₅P₂Ru: C, 59.41; H, 4.65; N, 3.08 Found: C, 59.10; H, 4.40;N, 2.70. ¹H NMR (200 MHz, toluene-d₈) δ 8.68 (t, J=8.5 Hz, 2H),8.25-8.10 (m, 2H), 7.99 (t, J=8.1 Hz, 2H), 7.75 (t, J=8.5 Hz, 2H),7.40-7.24 (m, 2H), 7.16-6.83 (m, 15H), 6.64-6.43 (m, 3H), 6.15-5.92 (m,1H), 5.80 (s, 1H), 4.71 (s, 1H), 4.21 (s, 1H), 3.91 (s, 1H), 3.72 (s,1H), 3.48 (s, 1H), 2.54 (t, J=14.6 Hz, 1H), 2.41-2.25 (m, 1H), 1.84 (s,3H), 1.66 (s, 3H). ¹³C NMR (50 MHz, toluene-d8) δ 210.1 (d, J=17.6 Hz),178.3, 177.0 (d, J=2.8 Hz), 160.1 (d, J=3.9 Hz), 149.1, 136.0 (d, J=11.8Hz), 135.5, 134.5 (d, J=10.7 Hz), 133.2 (d, J=9.9 Hz), 130.9, 130.0 (d,J=17.4 Hz), 128.3, 127.3, 121.3 (d, J=15.4 Hz), 77.0 (d, J=3.8 Hz), 76.5(d, J=7.1 Hz), 75.3 (d, J=7.3 Hz), 75.0 (d, J=5.4 Hz), 74.8, 71.3 (d,J=5.3 Hz), 71.1 (d, J=3.5 Hz), 70.3 (d, J=5.8 Hz), 50.4, 26.1, 24.6 (d,J=5.8 Hz). ³¹P NMR (81.0 MHz, toluene-d8) δ 51.2 (d, J=29.1 Hz), 40.5(d, J=29.1 Hz). IR (cm⁻¹): 1959, 1609, 1586.

EXAMPLE 12 Synthesis of the Complex[Ru(OAc)(CO)((R,R)-dpen)(R-Josiphos)]OAc (14)

In an NMR tube the complex Ru(OAc)₂(CO)(R-Josiphos) (34) (32.0 mg, 0.04mmol, 1 equiv) suspended in 0.6 mL of toluene-d₈, was reacted with theligand (R,R)-dpen (8.2 mg, 0.04 mmol, 1 equiv). After stirring at roomtemperature for 2 h, the sample was characterized by NMR, showing that 2isomers of the desired product were obtained in a 4/1 ratio. The samplewas then dried under low pressure. Yield: 39.1 mg (97%). Anal. Calcd (%)for C₅₅H₅₄FeN₂O₅P₂Ru: C, 63.40; H, 5.22; N, 2.69; Found: C, 63.00; H,5.40; N, 2.50. ³¹P NMR (81.0 MHz, toluene-d8) δ 60.4 (d, J=35.8 Hz,minor dia), 51.0 (d, J=34.7 Hz, major dia), 41.1 (d, J=34.6 Hz, majordia), 25.7 (d, J=35.8 Hz, minor dia). IR (cm⁻¹): 1957, 1601, 1558

EXAMPLE 13 Synthesis of the Complex[Ru(OAc)(CO)((S,S)-dpen)(R-Josiphos)]OAc (15)

In an NMR tube the complex Ru(OAc)₂(CO)(R-Josiphos) (34) (29.9 mg, 0.04mmol, 1 equiv) suspended in 0.6 mL of toluene-d₈, was reacted with theligand (S,S)-dpen (8.0 mg, 0.04 mmol, 1 equiv). After stirring at roomtemperature for 2 h, the sample was characterized by NMR, showing that 2isomers of the desired product was obtained in a 7/3 ratio. The samplewas then dried under low pressure. Yield: 36.7 mg (98%). Anal. Calcd (%)for C₅₅H₅₄FeN₂O₅P₂Ru: C, 63.40; H, 5.22; N, 2.69; Found: C, 63.30; H,5.50; N, 2.60. ³¹P NMR (81.0 MHz, toluene-d₈) δ 53.8 (d, J=36.0 Hz,minor dia), 52.6 (d, J=34.4 Hz, major dia), 41.9 (d, J=34.5 Hz, majordia), 36.1 (d, J=36.1 Hz, minor dia). IR (cm⁻¹): 1956, 1602, 1562.

EXAMPLE 14 Synthesis of the Complex RuCl₂(CO)(Hamtp)(PPh₃) (16)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (282.3 mg, 0.35 mmol, 1 equiv),suspended in 15 mL of CHCl₃, was reacted with the ligand HCNN (70.9 mg,0.36 mmol, 1.1 equiv). The suspension was stirred at 60° C. overnightand the volume was reduced to about 1 mL. The complex was precipitatedby addition of 10 mL of n-pentane. The obtained solid was filtered,washed two times with 5 mL of ethyl ether, one time with 5 mL ofn-pentane and dried under reduced pressure. Yield: 160,3 mg (69%). Anal.Calcd (%) for C₃₂H₂₉Cl₂N₂OPRu:C, 58.19; H, 4.43; N, 4.24; found: C,58.20, H, 4.40; N, 4 . . . ¹H NMR (200 MHz, CD₂Cl₂) δ 7.89-7.07 (m,22H), 4.50 (t, J=6.1 Hz, 2H), 3.13 (t, J=5.7 Hz, 2H), 2.49 (s, 3H). ¹³CNMR (50 MHz, CD₂Cl₂) δ 200.7 (d, J=21.5 Hz), 165.5, 161.4, 140.4, 139.4,137.1, 134.1 (d, J=9.6 Hz), 133.2, 132.3, 130.27, 130.2 (d, J=2.4 Hz),129.3, 128.3 (d, J=10.0 Hz), 126.0 (d, J=2.3 Hz), 119.8 (d, J=1.4 Hz),66.0, 50.3, 21.6 (d, J=12.2 Hz). ³¹P NMR (81 MHz, CD₂Cl₂) δ 54.5. IR(cm⁻¹): 1947.

EXAMPLE 15 Synthesis of the Complex RuCl₂(CO)(Hambq)(PPh₃) (17)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (365 mg, 0.46 mmol, 1 equiv),suspended in 5 mL of n-BuOH, was reacted with the ligand Hambq (208 mg,1.03 mmol, 2.2 equiv). The suspension was stirred at 130° C. overnight,the solvent was evaporated under reduced pressure and the residue wasdissolved in 1 mL of CHCl₃. The solution was stirred for 1 hour at roomtemperature and the complex was precipitated by addition of 10 mL ethylether. The solution was filtered, and the solid was washed 2 times with3 mL of ethyl ether, one time with 3 mL of n-pentane and dried underreduced pressure. Yield: 291 mg (95%). Anal. Calcd (%) forC₃₃H₂₇Cl₂N₂OPRu: C, 59.11; H, 4.06; N, 4.18, found: C, 59.20; H, 4.10;N, 4.26. ¹H NMR (200 MHz, CD₂Cl₂) δ 8.12-6.87 (m, 23H), 4.36-4.14 (m,1H), 4.01-3.83 (m, 1H), 3.54-3.28 (m, 1H), 2.68-2.24 (m, 1 H). ³¹P NMR(81 MHz, CD₂Cl₂) δ 36.9. IR (cm⁻¹): 1920.

EXAMPLE 16 Synthesis of the Complex RuCl₂(CO)(Hambq^(Ph))(PPh₃) (18)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (245 mg, 0.31 mmol, 1 equiv),suspended in 5 mL of n-BuOH, was reacted with the ligand HCl.Hambg^(Ph)(159 mg, 0.50 mmol, 1.6 equiv) and the base n-Bu₃N (0.5 mL, 2 mmol, 6.6equiv). After stirring at 130° C. overnight, the solvent was evaporatedunder reduced pressure, the residue dissolved in 3 mL of CHCl₃ and thebase K₂CO₃ (200 mg, 1.39 mmol, 4.5 equiv) was added. The mixture wasstirred for 2 h at room temperature, the mixture was filtered. Thevolume was reduced to about 1 mL and the complex was precipitated byaddition of 10 mL ethyl ether. The solution was filtered, and the solidwas washed 2 times with 3 mL of ethyl ether, one time with 3 mL ofn-pentane and dried under reduced pressure. Yield: 101 mg (46%). Anal.Calcd (%) for C₃₉H₃₁Cl₂N₂OPRu: C, 62.74; H, 4.18; N, 3.75, found: C,62.66; H, 4.10; N, 3.92. ¹H NMR (200 MHz, CD₂Cl₂) δ 9.21-9.13 (m, 1H),7.95-7.10 (m, 26H), 4.77-4.54 (m, 1H), 4.26-4.00 (m, 1H), 3.84-3.63 (m,1H), 3.19-2.98 (m, 1H). ³¹P NMR (81 MHz, CD₂Cl₂) δ 36.9. IR (cm⁻¹):1924.

EXAMPLE 17 Synthesis of the Complex Ru(OAc)₂(Hamtp)(CO)(PPh₃) (19)

The complex Ru(OAc)₂(CO)(PPh₃)₂ (100,3 mg, 0.13 mmol, 1 equiv),suspended in 5 mL of toluene, was reacted with the ligand Hamtp (26,7mg, 0.13 mmol, 1 equiv). After stirring at 110° C. for 2 days, thesolution was concentrated to V˜0.5 mL, and the complex was precipitatedby addition of 7 mL of n-pentane . The mixture was filtered and thesolid was washed 2 times with 5 mL of n-Heptane, two times with 3 mL ofEt₂O and dried under reduced pressure. Yield: 37,1 mg (40%). Anal. Calcd(%) for C₃₆H₃₅N₂O₅PRu: C, 61.10; H, 4.98; N, 3.96, found: C, 60.90; H,5.30; N, 3.80. ¹H NMR (200 MHz, CD₂Cl₂) δ 8.28-8.02 (m, 1 H), 7.79-7.60(m, 6H), 7.46-7.37 (m, 6H), 7.30-7.17 (m, 6H), 7.10-7.03 (m, 1 H), 6.91(d, J=8.4 Hz, 1H), 6.73-6.58 (m, 1 H), 4.41 (dd, J=16.6, 6.5 Hz, 1 H),4.32-4.07 (m, 2H), 3.53-3.30 (m, 1 H), 2.14 (s, 3H), 2.07 (s, 3H), 1.20(s, 3H). ³¹P NMR (81 MHz, CD₂Cl₂) δ 54,4. IR (cm⁻¹): 1914, 1597, 1572.

EXAMPLE 18 Synthesis of the Complex RuCl(amtp)(CO)(PPh₃) (20)

The complex RuCl(CNN)(PPh₃)₂ (251.9 mg, 0.29 mmol, 1 equiv) wassuspended in 5 mL of CH₂Cl₂ and the mixture was stirred under COatmosphere (1 atm) overnight at room temperature. The solvent wasevaporated under reduced pressure and the residue was purified by columnchromatography, eluent CH₂Cl₂/Et₂O (9/1 to 1/1). Yield: 173 mg (94%).Anal. Calcd (%) for C₃₂H₂₈ClN₂OPRu: C, 61.59; H, 4.52; N, 4.49. Found:C, 61.74; H, 4.85; N, 4.66. IR (cm⁻¹): 1905.

EXAMPLE 19 Synthesis of the Complex RuCl(ambq)(CO)(PPh₃) (21)

The complex RuCl(ambq)(PPh₃)₂ (226 mg, 0.26 mmol, 1 equiv) was suspendedin 5 mL of CH₂Cl₂, and the mixture was stirred under CO atmosphere (1atm) overnight at room temperature. The solvent was evaporated underreduced pressure and the residue was purified by column chromatography,eluent CH₂Cl₂/Et₂O (9/1 to 1/1). Yield: 132 mg (80%). Anal. Calcd (%)for C₃₃H₂₆ClN₂OPRu: C, 62.51; H, 4.13; N, 4.42. Found:C, 62.55; H, 4.10;N, 4.37. ¹H NMR (200 MHz, CD₂Cl₂) δ 8.06-7.80 (m, 2H), 7.51-6.92 (m,20H), 4.53 (dd, J=16.9, 6.7 Hz, 1H), 4.13-3.96 (m, 1H), 3.85-3.60 (m,1H), 2.76 (t, J=8.7 Hz, 1H) . ¹³C NMR (50 MHz, CD₂Cl₂) δ 207.9 (d,J=17.5 Hz), 172.2 (d, J=12.8 Hz), 156.1, 150.7, 142.5, 139.8, 135.5,134.1 (d, J=19.2 Hz), 133.4, 133.0 (d, J=10.2 Hz), 133.0 (s,), 130.1 (d,J=2.3 Hz), 129.6, 128.3 (d, J=9.8 Hz), 125.5, 122.4, 119.8, 116.7, 51.5.³¹P NMR (81 MHz, CD₂Cl₂) δ 58.4. IR (cm⁻¹): 1922.

EXAMPLE 20 Synthesis of the Complex RuCl(ambq^(Ph))(CO)(PPh₃) (22)

The complex RuCl(ambq^(Ph))(PPh₃)₂ (119.8 mg, 0.13 mmol, 1 equiv) wassuspended in 5 mL of CH₂Cl₂ and the mixture stirred under CO atmosphere(1 atm) at room temperature overnight. The solvent was evaporated underreduced pressure and the residue was purified by column chromatography,eluent CH₂Cl₂/Et₂O (9/1 to 1/1). Yield: 76.6 mg (85%). Anal. Calcd (%)for C₃₉H₃₀ClN₂OPRu: C, 65.96; H, 4.26; N, 3.94. Found: C, 66.31; H,3.33; N, 4.12. ¹H NMR (200 MHz, CD₂Cl₂) δ 8.17-6.89 (m, 26H), 4.57 (dd,J=16.9, 6.5 Hz, 1H), 4.14 (dd, J=17.4, 10.0 Hz, 1H), 3.83 (dd, J=17.0,7.6 Hz, 1H), 2.99 (dd, J=9.1, 7.0 Hz, 1H). ¹³C NMR (50 MHz, CD₂Cl₂) δ208.0 (d, J=17.4 Hz, CO), 172.6 (d, J=12.8 Hz, Ru—C), 155.8, 150.9,148.7, 142.7, 139.9, 138.0, 134.0 (d, J=9.1 Hz), 133.1, 132.9, 132.9,130.0 (d, J=2.4 Hz), 129.9, 129.6, 129.1, 128.8, 128.3 (d, J=9.8 Hz),123.6, 120.6, 119.6, 117.2, 51.5. ³¹P NMR (81 MHz, CD₂Cl₂) δ 58.8. IR(cm⁻¹): 1920.

EXAMPLE 21 Synthesis of the Complex RuCl[(2-CH₂-6-Me-C₆H₃)PCy₂](CO)(en)(23)

In an NMR tube the complexRuCl[(2-CH₂-6-Me-C₆H₃)PCy₂](CO)[(2,6-Me₂C₆H₃)PCy₂] (25) (15.5 mg, 0.02mmol, 1 equiv) was dissolved in 0.6 mL of CD₂Cl₂. The ligand en (3 μL,0.04 mmol, 2 equiv) was added. The solution was heated at 50° C. for twodays. The ³¹P NMR analysis of the tube showed the displacement of oneligand PCy₂(Xylyl) and the formation of two isomers of the desiredcomplex 23. ³¹P NMR (81 MHz, CD₂Cl₂) δ 97.4 (s, 1%), 84.5 (s, 35%), 81.1(s, 23%), 53.1 (s, 5%, OPCy₂(Xylyl)), −4.23 (s, 37%, PCy₂(Xylyl)).

EXAMPLE 22 Synthesis of the ComplexRuCl[(2-CH₂-6-Me-C₆H₃)PCy₂](CO)(ampy) (24)

In an NMR tube the complexRuCl[(2-CH₂-6-Me-C₆H₃)PCy₂](CO)[(2,6-Me₂C₆H₃)PCy₂] (25) (15.5 mg, 0.02mmol, 1 equiv) was dissolved in 0.6 mL of CD₂Cl₂. The ligand en (3 μL,0.04 mmol, 2 equiv) was added. The solution was heated at 50° C. for twodays with formation of complex 24.

EXAMPLE 23 Synthesis of the ComplexRuCl[(2-CH₂-6-Me-C₆H₃)PCy₂](CO)[(2,6-Me₂C₆H₃)PCy₂] (25)

The complex RuCl₃.xH₂O (109 mg, 0.43 mmol, 1 equiv), suspended in 4 mLof EtOH, was reacted with the ligand (2,6-Me₂C₆H₃)PCy₂ (345 mg, 1.14mmol, 2.7 equiv) and the base Et₃N (250 μL, 1.84 mmol, 4.3 equiv). Afterstirring at 80° C. for 1 h, formaldehyde (300 μL, 37% solution in water,3.70 mmol, 8.6 equiv) was added and the mixture was stirred at 80° C.overnight. The volume was reduced to about half and the obtainedprecipitated was filtered. The solid was washed two times with 2 mL ofEtOH, once with 2 mL of Et₂O and dried under reduced pressure. Yield:107 mg (32%). Anal. Calcd (%) for C₄₁H₆₁ClOP₂Ru: C, 64.09; H, 8.00,Found: C, 63.99; H, 8.95. ¹H NMR (200 MHz, CD₂Cl₂) δ 7.32-6.86 (m, 6H),3.78 (d, J=12.9 Hz, 1H), 3.58 (dd, J=15.0, 6.7 Hz, 1H), 2.97-1.11 (m,53H). ¹³C NMR (50 MHz, CD₂Cl₂) δ 201.6 (dd, J=14.4, 12.1 Hz), 163.7 (dd,J=33.6, 4.2 Hz), 140.8 (d, J=1.4 Hz), 133.8 (d, J=3.0 Hz), 131.3 (d,J=1.4 Hz), 130.9 (d, J=1.7 Hz), 130.5 (d, J=2.5 Hz), 130.1 (d, J=2.1Hz), 129.8 (d, J=0.9 Hz), 129.5 (d, J=2.4 Hz), 129.1 (d, J=1.1 Hz),128.9 (d, J=1.3 Hz), 127.7 (d, J=5.5 Hz), 126.0 (d, J=14.4 Hz), 41.7 (d,J=19.2 Hz), 40.6, 39.4 (d, J=13.7 Hz), 39.2 (d, J=8.1 Hz), 35.4 (d,J=13.9 Hz), 33.9 (d, J=25.5 Hz), 32.6 (d, J=5.9 Hz), 31.6 (d, J=4.6 Hz),30.8 (d, J=10.5 Hz), 30.6 (d, J=3.1 Hz), 30.1 (d, J=4.1 Hz), 29.9, 29.6(d, J=4.0 Hz), 29.3, 28.8 (d, J=8.5 Hz), 28.5-25.8 (m), 23.7 (d, J=2.2Hz), 23.2 (t, J=4.0 Hz), 22.7. ³¹P NMR (81 MHz, CD₂Cl₂) δ 67.2 (d,J=281.4 Hz), 40.0 (d, J=281.6 Hz). IR (cm⁻¹): 1903.

EXAMPLE 24 Synthesis of RuCl₂(CO)(dppb)(PPh₃) (27)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (100.9 mg, 0.13 mmol, 1 equiv)suspended in 5 mL of CHCI3, was reacted with the ligand dppb (54.6 mg,0.13 mmol, 1 equiv). After stirring at 60° C. overnight, the solutionwas concentrated to about 1 mL. The complex was precipitated by additionof 10 mL n-heptane. The obtained solid was filtered, washed 3 times with4 mL of n-heptane, 3 times with 3 mL of ethyl ether and dried underreduced pressure. Yield: 112.4 mg (75%). Anal. Calcd (%) forC₄₇H₄₃Cl₂OP₃Ru: C, 63.52; H, 4.88 Found: C, 64.93; H, 5.99. ¹H NMR (200MHz, CDCI3) δ 7.85-7.70 (m, 4H), 7.66-6.97 (m, 28H), 6.89-6.69 (m, 3H),3.15-2.95 (m, 1H), 2.72-2.40 (m, 3H), 2.34-2.16 (m, 2H), 1.77-1.52 (m,2H). ³¹P NMR (81 MHz, CD₂Cl₂) δ 27.5 (t, J=25.8 Hz, 1P), 16.4-14.8 (m,2P). IR (cm⁻¹): 1954.

EXAMPLE 25 Synthesis of RuCl₂(CO)(dppf) (28)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (199.3 mg, 0.25 mmol, 1 equiv)suspended in 5 mL of toluene, was reacted with the ligand dppf (141.3mg, 0.25 mmol, 1 equiv). After stirring the mixture at 110° C. for 2 h,the obtained solution was concentrated to about 1 mL, 10 mL n-heptanewere added and the suspension was stirred at room temperature for 1 h.The precipitate was filtered, the obtained solid was washed 3 times with4 mL of n-heptane, 3 times with 3 mL of ethyl ether and dried underreduced pressure. Yield: 99.5 mg (39%). Anal. Calcd (%) forC₃₅H₂₈Cl₂FeOP₂Ru: C, 55.73; H, 3.74 Found: C, 55.41; H, 3.33. ³¹P NMR(81 MHz, CD₂Cl₂) δ 53.6 (d, J=27.2 Hz), 46.6 (d, J=26.8 Hz). IR (cm⁻¹):1979.

EXAMPLE 26 Synthesis of RuCl₂(CO)((R)-Josiphos)(PPh₃) (29)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (300.0 mg, 0.38 mmol, 1 equiv)suspended in 5 mL of toluene, was reacted with the ligand (R)-Josiphos(225.2 mg, 0.39 mmol, 1 equiv). After stirring the mixture at 110° C. 2h, the obtained solution was concentrated to about 1 mL. The complex wasprecipitated by addition of 10 mL n-heptane, filtered, washed 3 timeswith 4 mL of n-heptane, 3 times with 3 mL of ethyl ether and dried underreduced pressure. Yield: 345.8 mg. Anal. Calcd (%) for C₅₅H₄₇Cl₂FeOP₃Ru:C, 63.23; H, 4.53; Found: C, 62.90; H, 4.20. ³¹P NMR (81 MHz, CD₂Cl₂) δ47.5 (t, J=22.9 Hz), 13.6 (d, J=22.7 Hz). IR (cm⁻¹): 1979.

EXAMPLE 27 Synthesis of RuCl₂(CO)((R)-BINAP)(PPh₃) (30)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (299.7 mg, 0.38 mmol, 1 equiv)suspended in 5 mL of toluene, was reacted with the ligand (R)-BINAP(239.8 mg, 0.39 mmol, 1 equiv). After stirring at 110° C. 2 h, theobtained solution was concentrated to about 1 mL. The complex wasprecipitated by addition of 10 mL n-heptane, filtered, washed 3 timeswith 4 mL of n-heptane, 3 times with 3 mL of ethyl ether and dried underreduced pressure. Yield: 359.7 mg (87%). Anal. Calcd (%) forC₆₃H₄₈Cl₂OP₃Ru: C, 69.68; H, 4.37; Found: C, 69.80; H, 4.10. IR (cm⁻¹):1981

EXAMPLE 28 Synthesis of RuCl₂(CO)((R,R)-Skewphos)(PPh₃) (31)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (201.1 mg, 0.26 mmol, 1 equiv)suspended in 5 mL of toluene, was reacted with the ligand (R,R)-Skewphos(113.0 mg, 0.26 mmol, 1 equiv). After stirring at 110° C. 2 h, thesolution was concentrated to about 1 mL. The complex was precipitated byaddition of 10 mL n-heptane, filtered, washed 3 times with 4 mL ofn-heptane, 3 times with 3 mL of ethyl ether and dried under reducedpressure. Yield: 150.5 mg (65%). IR (cm⁻¹): 1976.

EXAMPLE 29 Synthesis of Ru(OAc)₂(CO)(dppb) (32)

The complex Ru(OAc)₂(CO)(PPh₃)₂ (300.3 mg, 0.39 mmol, 1 equiv) suspendedin 5 mL of CH₂Cl₂, was reacted with the ligand dppb (167.3 mg, 0.39mmol, 1 equiv). After stirring the mixture at room temperatureovernight, the obtained solution was concentrated to about 0.5 mL. Thecomplex was precipitated by addition of 10 mL n-heptane, filtered,washed 3 times with 4 mL of n-heptane, 3 times with 3 mL of ethyl etherand dried under reduced pressure. Yield: 230.1 mg (88%). Anal. Calcd (%)for C₃₃H₃₄O₅P₂Ru: C, 58.84; H, 5.09 Found: C, 58.50; H, 5.10.¹H NMR (200MHz, CDCl₃, 25° C.) δ 7.92-7.12 (m, 20H), 2.84 (m, 2H), 2.43 (m, 2H),1.79 (m, 4H), 1.41 (s, 6H). ¹H NMR (200 MHz, CDCl₃, −70° C.) δ 8.07-7.77(m, 3H), 7.73-7.19 (m, 15H), 7.15-6.92 (m, 2H), 3.37-2.36 (m, 3H),2.29-1.38 (m, 5H), 1.34 (s, 3H), 1.14 (s, 3H). ¹³C NMR (50 MHz, CD₂Cl₂,25° C.) δ 204.6 (broad), 133.77-132.48 (m), 130.80 (d, J=25.6 Hz),129.07-128.33 (m), 30.40 (s, broad), 29.75 (s, broad), 23.79 (s, broad),23.53 (s, broad). ¹³C NMR (50 MHz, CD₂Cl₂, −70° C.) δ 204.5 (dd, J=21.6,15.8 Hz), 202.7 (t, J=16.9 Hz), 189.1, 182.4 (t, J=38.8 Hz), 175.3,136.8 (d, J=51.5 Hz), 133.4 (d, J=18.8 Hz), 131.8, 131.2-130.5 (m),130.4 (d, J=8.7 Hz), 129.4 (d, J=17.3 Hz), 129.1-128.5 (m), 128.0 (d,J=8.9 Hz), 127.8 (d, J=9.5 Hz) 29.9 (d, J=35.3 Hz), 27.7 (d, J=33.5 Hz),25.2, 24.4, 21.9 (d, J=4.3 Hz), 20.5. ³¹P NMR (81 MHz, CD₂Cl₂, 25° C.) δ46.7 (broad). ³¹P NMR (81 MHz, CD₂Cl₂, −70° C.) δ 48.0 (d, J=27.1 Hz),46.3 (d, J=25.9 Hz), 38.7 (s, broad). IR (cm⁻¹): 1954, 1945.

EXAMPLE 30 Synthesis of Ru(OAc)₂(CO)(dppf) (33)

The complex Ru(OAc)₂(CO)(PPh₃)₂ (200.5 mg, 0.26 mmol, 1 equiv) suspendedin 5 mL of toluene, was reacted with the ligand dppf (167.3 mg, 0.26mmol, 1 equiv). After stirring at 110° C. for 2 h, the solution wasconcentrated to about 1 mL and the complex was precipitated by additionof 10 mL n-heptane, filtered, washed 3 times with 4 mL of n-heptane, 3times with 3 mL of ethyl ether and dried under reduced pressure. Yield:139.6 mg (67%) determined to be a mixture of 3 isomers in a ratio of7/2/1 at -70° C., the mixture is interchanging at room temperature.Anal. Calcd (%) for C₃₉H₃₄FeO₅P₂Ru: C, 58.44; H, 4.28; Found: C, 58.10;H, 4.60. ¹H NMR (200 MHz, CDCl₃, 25° C.) δ 7.95-7.14 (m broad, 20 H),4.68-4.24 (m broad, 8H), 1.56 (s broad, 6H). ¹³C NMR (50 MHz, CD₂Cl₂,25° C.) δ 134.9-133.1 (m), 130.7 (d, J=16.0 Hz), 129.1-127.2 (m), 75.5(d, J=36.2 Hz), 73.1, 72.6, 24.2 (s, broad). ¹³C NMR (50 MHz, CD₂Cl₂,−70° C.) δ 203.07 (t, J=16.5 Hz), 182.69 (s), 181.93 (s), 134.64 (dd,J=22.9, 9.9 Hz), 132.95 (d, J=9.7 Hz), 132.24-130.81 (m), 129.84 (s),127.92-126.43 (m), 78.20-76.66 (m), 75.95 (d, J=5.4 Hz), 75.53-74.02(m), 72.71 (s), 71.80 (d, J=6.1 Hz), 71.14 (d, J=5.4 Hz), 25.40 (s),24.47 (d, J=4.8 Hz). ³¹P NMR (81 MHz, CD₂Cl₂, 25° C.) δ 50.8 (s broad).³¹P NMR (81 MHz, CD₂Cl₂, −70° C.) δ 53.1 (d, J=27.1 Hz, 10%), 52.0 (d,J=26.7 Hz, 23%), 49.8 (d, J=30.4 Hz), 45.4 (d, J=30.4 Hz, 67%), 43.5 (d,J=26.8 Hz, 10%). IR (cm⁻¹): 1974, 1613.

EXAMPLE 31 Synthesis of Ru(OAc)₂(CO)((R)-Josiphos) (34)

The complex Ru(OAc)₂(CO)(PPh₃)₂ (300.3 mg, 0.39 mmol, 1 equiv) suspendedin 5 mL of toluene, was reacted with the ligand (R)-Josiphos (167.3 mg,0.40 mmol, 1 equiv). After stirring at 110° C. for 2 h, the homogenoussolution, was concentrated to about 1 mL and the complex wasprecipitated by addition of 10 mL n-heptane, filtered, washed 3 timeswith 4 mL of n-heptane, 3 times with 3 mL of ethyl ether and dried underreduced pressure, leading to a mixture of two diastereoisomers of theproduct in a 3/2 ratio. Yield: 273.6 mg (85%). Anal. Calcd (%) forC₄₁H₃₈FeO₅P₂Ru: C, 59.36; H, 4.62 Found: C, 59.30; H, 4.30. ¹H NMR (200MHz, CD₂Cl₂, 25° C.) δ 8.25-7.99 (m, 3H), 7.70-7.07 (m, 31 H), 7.05-6.87(m, 2H), 6.72-6.46 (m, 2H), 4.81 (s, 1 H, maj dia), 4.65 (s, 1H mindia), 4.49 (s, 1H), 4.44-4.32 (m, 2H), 4.24-4.00 (m, 2H), 3.91 (s, 3Hmin dia), 3.76 (s, 5H maj dia), 2.09-1.65 (m, 4H), 1.51-1.25 (m, 8H).³¹P NMR (81 MHz, CD₂Cl₂, 25° C.) δ 67.2 (broad, maj dia), 46.5 (broad,maj dia), 35.9 (broad, min dia), 30.5 (broad, min dia). IR (cm⁻¹): 1975,1950, 1614, 1568.

EXAMPLE 32 Synthesis of Ru(OAc)₂(CO)((R)-BINAP) (35)

The complex Ru(OAc)₂(CO)(PPh₃)₂ (300.7 mg, 0.39 mmol, 1 equiv) suspendedin 5 mL of toluene, was reacted with the ligand (R)-BINAP (243 mg, 0.39mmol, 1 equiv). After stirring at 110° C. for 2 h, the solution wasconcentrated to about 1 mL. The complex was precipitated by addition of10 mL n-heptane, filtered, washed 3 times with 4 mL of n-heptane, 3times with 3 mL of ethyl ether and dried under reduced pressure. Yield:314.1 mg (93%). Anal. Calcd (%) for C₄₉H₃₈O₅P₂Ru: C, 67.66; H, 4.40Found: C, 68.00; H, 4.30. ¹H NMR (200 MHz, CD₂Cl₂, 25° C.) δ 7.97-7.81(m, 2H), 7.71-7.27 (m, 20H), 7.24-6.99 (m, 4H), 6.92-6.52 (m, 6H), 1.29(s, 6H). ³¹P NMR (81 MHz, CD₂Cl₂, 25° C.) δ 49.87 (s broad), 43.21 (sbroad). IR (cm⁻¹): 1968, 1616, 1505.

EXAMPLE 33 Synthesis of Ru(OAc)₂(CO)((R,R)-Skewphos) (36)

The complex Ru(OAc)₂(CO)(PPh₃)₂ (200.9 mg, 0.26 mmol, 1 equiv) suspendedin 5 mL of toluene, was reacted with the ligand (R,R)-Skewphos (114 mg,0.26 mmol, 1 equiv). After stirring at 110° C. for 2 h, the solution wasconcentrated to about 1 mL and the complex was precipitated by additionof 10 mL n-heptane, filtered, washed 3 times with 4 mL of n-heptane, 3times with 3 mL of Et₂O and dried under reduced pressure. Yield: 127.9mg (71%). Anal. Calcd (%) for C₃₄H₃₆O₅P₂Ru: C, 59.38; H, 5.28 Found: C,59.20; H, 4.90; N, 4.10. ¹H NMR (200 MHz, CD₂Cl₂, 25° C.) δ 7.78-7.34(m, 16H), 7.32-7.08 (m, 4H), 3.28-3.03 (m, 1 H), 2.85-2.64 (m, 1 H),2.26-2.06 (m, 1H), 2.00-1.77 (m, 1H), 1.57 (s broad, 6H), 0.95 (ddd,J=19.4, 14.0, 7.1 Hz, 6H). ³¹P NMR (81 MHz, CD₂Cl₂, 25° C.) δ 55.0 (s,broad), 50.9 (s, broad). IR (cm−1): 1958, 1568.

EXAMPLE 34 Synthesis of RuCl₂(CO)(dppb)(HCN) (37)

The complex RuCl₂(CO)(dmf)(PPh₃)₂ (159.1 mg, 0.20 mmol, 1 equiv)suspended in 3 mL of CH₂Cl₂, was reacted with the ligand dppb (85.3 mg,0.20 mmol, 1 equiv) and stirred at room temperature for 2 h. Thesolution was dried under vacuum and 2-propanol (3 ml) and the ligand HCN(0.3 mmol, 33 μl, 1.5 eq.) were sequentially added to the obtainedresidue and the mixture refluxed for 2.5 h. The solvent was evaporatedunder reduced pressure and the crude product was treated with n-pentaneand refluxed for 0.5 h. The precipitated complex was filtrated, washed 3times with 4 mL of pentane and dried under reduced pressure. Yield: 92mg (63%). ³¹P NMR (81 MHz, CD₂Cl₂, 25° C.) δ 47.6 (d, J=30.2 Hz), 28.2(d, J=30.2 Hz).

EXAMPLE 35 Synthesis of Ru(OAc)₂(CO)(dppb)(HCN) (38)

The complex Ru(OAc)₂(CO)(PPh₃)₂ (154.3 mg, 0.20 mmol, 1 equiv) suspendedin 3 mL of CH₂Cl₂, was reacted with the ligand dppb (85.3 mg, 0.20 mmol,1 equiv) and stirred at room temperature for 2 h. The solvent wasevaporated under reduced pressure and 2-propanol (3 ml) and the ligandHCN (0.3 mmol, 33 μl, 1.5 eq.) were sequentially added and the mixturewas refluxed for 2.5 h. The solvent was evaporated under reducedpressure and the crude product was treated with pentane and refluxed for0.5 h (3×3 ml). The precipitated complex was filtrated and dried underreduced pressure. Yield: 90 mg (58%). ³¹P NMR (81 MHz, CD₂Cl₂, 25° C.) δ45.1 (d, J=29.1 Hz), 34.7 (d, J=29.1 Hz).

EXAMPLE 36 Synthesis of Ru(OAc)₂(CO)(PNN) (39)

The complex Ru(OAc)₂(CO)(PPh₃)₂ (201.2 mg, 0.26 mmol, 1 equiv) suspendedin 5 mL of toluene, was reacted with the ligand PNN (101.4 mg, 0.27mmol, 1 equiv). After stirring at 110° C. for 2 h, the solution wasconcentrated to about 1 mL. The complex was precipitate by addition of10 mL n-heptane, filtrated, washed 3 times with 4 mL of n-heptane, 3times with 3 mL of ethyl ether and dried under reduced pressure. Yield:142.1 mg (87%). Anal. Calcd (%) for C₃₀H₂₉N₂O₅PRu: C, 57.23; H, 4.64; N,4.45 Found: C, 57.60; H, 4.50; N, 4.10. ¹H NMR (200 MHz, CD₂Cl₂) δ9.04-8.92 (m, 1H), 8.36 (s, 1H, N-H), 7.93-7.56 (m, 6H), 7.56-7.32 (m,6H), 7.32-7.12 (m, 4H), 6.97-6.83 (m, 1 H), 4.15-4.07 (m, 2H), 3.82-3.64(m, 1 H), 3.52-3.36 (m, 1H), 1.55 (s, 3H), 1.25 (s, 3H). ¹³C NMR (50MHz, CD₂Cl₂) δ 205.0 (d, J=16.5 Hz), 176.5, 176.2, 168.5 (d, J=5.7 Hz),161.3, 151.7, 138.3, 137.9, 135.8 (d, J=8.7 Hz), 134.6 (d, J=9.9 Hz),134.1, 134.1 (d, J=10.3 Hz), 132.6 (d, J=6.3 Hz), 131.5 (d, J=2.1 Hz),130.8 (d, J=2.6 Hz), 130.7 (d, J=3.6 Hz), 130.0, 129.4, 128.7 (d, J=10.3Hz), 128.2 (d, J=10.5 Hz), 125.1 (d, J=2.8 Hz), 122.8 (d, J=2.3 Hz),63.5, 37.2, 24.4, 23.6. 31 P NMR (81 MHz, CD₂Cl₂) δ 49.0. IR (cm−1):1940, 1626, 1607.

EXAMPLE 37 Catalytic Reduction by Transfer Hydrogenation of Ketones andAldehydes with Complexes of Examples 1-39

The catalyst solution was prepared in a 10 mL Schlenk by adding 5 mL of2-propanol to the chosen ruthenium complex (0.02 mmol). By stirring, thecomplex dissolved over a period of a few minutes. Separately, in asecond Schlenk (20 mL), 250 μL of the previously prepared solutioncontaining the catalyst and 200 μL of a 0.1 M sodium iso-propoxidesolution in 2-propanol were added successively to a ketone or aldehydesolution (1 mmol) in 10 mL of 2-propanol under reflux (S/C=1000,S/B=50).

For the reactions, in which the catalyst was formed in situ, apre-catalyst solution was prepared by adding 5 mL of 2-propanol to thepre-catalyst (0.02 mmol) and the corresponding ligand (0.1 mmol) (seeTables 2 and 3) and the solution was stirred for 30 min at reflux. Thesolution of the in situ formed catalyst was used in the reductionreaction as described above (S/C=1000, L/C=5, S/B=50).

The start of the reaction was considered to be when the base was added.The molar ratio of substrate/catalyst (S/C) varied from 1000/1 to50000/1 while the molar ratio substrate/base was in the range of 10/1 to100/1.

The reaction temperature was kept at 82° C.

The results of the GC analysis for the reduction of acetophenone arereported in Table 2, while those for other ketones and aldehydes areshown in Table 3.

TABLE 2 Catalytic transfer hydrogenation of acetophenone (0.1M) to1-phenylethanol with the complexes 1-39 and NaOiPr or K₂CO₃ as baseConversion Complex S/C Ligand Base (S/B) % (min) TOF (h⁻¹)^(a) ee (%) 11000 — NaOiPr (50/1) 54 (90) — 2 1000 — NaOiPr (50/1) 42 (60) — 3 1000 —NaOiPr (50/1) 27 (90) 4 + 5 1000 — NaOiPr (50/1) 81 (90) 6 + 7 1000 —NaOiPr (50/1) 95 (90) 8 1000 — NaOiPr (50/1) 90 (90) 9 1000 — NaOiPr(50/1) 88 (90) 16 1000 — NaOiPr (50/1) 100 (2) 12000 16 10000 — NaOiPr(50/1) 100 (36) 8000 18 10000 — NaOiPr (50/1) 100 (17) 20000 20 10000 —NaOiPr (50/1) 100 (0.06) 86000 20 50000 — NaOiPr (50/1) 100 (0.45) 5500021 1000 — K₂CO₃ (20/1) 95 (30) 21 1000 — NaOiPr (50/1) 96 (15) 22 10000— NaOiPr (50/1) 100 (17) 18000 27 1000 en NaOiPr (50/1) 25 (120) — 271000 ampy NaOiPr (50/1) 38 (120) — 28 1000 en NaOiPr (50/1) 44 (120) —28 1000 ampy NaOiPr (50/1) 90 (120) 3500 29 1000 en NaOiPr (50/1) 74(120) 400 13 29 1000 ampy NaOiPr (50/1) 95 (120) 1700 17 29 1000(±)iPr-ampy NaOiPr (50/1) 97 (30) 6700 17 29 1000 (R,R)-DPEN NaOiPr(50/1) 96 (120) 1200 59 29 1000 (S,S)-DPEN NaOiPr (50/1) 94 (120) 700 3230 1000 en NaOiPr (50/1) 92 (120) 900 22 30 1000 ampy NaOiPr (50/1) 88(300) 300 18 30 1000 (±)iPr-ampy NaOiPr (50/1) 97 (120) 1200 25 30 1000(R,R)-DPEN NaOiPr (50/1) 93 (120) 8400 32 30 1000 (S,S)-DPEN NaOiPr(50/1) 78 (120) 1100 16 31 1000 en NaOiPr (50/1) 48 (120) — 13 31 1000ampy NaOiPr (50/1) 86 (120) 1800 66 31 1000 (±)iPr-ampy NaOiPr (50/1) 95(30) 5800 67 31 1000 (R,R)-DPEN NaOiPr (50/1) 85 (120) 800 46 31 1000(S,S)-DPEN NaOiPr (50/1) 46 (120) 300 53 32 1000 en NaOiPr (50/1) 85(120) 3700 32 1000 ampy NaOiPr (50/1) 93 (120) 7400 33 1000 en NaOiPr(50/1) 46 (120) — 33 1000 ampy NaOiPr (50/1) 72 (120) 6850 34 1000 enNaOiPr (50/1) 91 (120) 1200 9 34 1000 ampy NaOiPr (50/1) 94 (30) 10650 234 1000 (±)iPr-ampy NaOiPr (50/1) 94 (5) 16000 22 34 1000 (R,R)-DPENNaOiPr (50/1) 96 (30) 16000 23 34 1000 (S,S)-DPEN NaOiPr (50/1) 96 (30)16000 1 35 1000 en NaOiPr (50/1) 97 (30) 6000 18 35 1000 ampy NaOiPr(50/1) 94 (5) 16800 23 35 1000 (±)iPr-ampy NaOiPr (50/1) 97 (5) 19200 2435 1000 (R,R)-DPEN NaOiPr (50/1) 97 (5) 15000 30 35 1000 (S,S)-DPENNaOiPr (50/1) 96 (5) 12000 19 36 1000 en NaOiPr (50/1) 91 (30) 10100 2536 1000 ampy NaOiPr (50/1) 95 (30) 10100 25 36 1000 (±)iPr-ampy NaOiPr(50/1) 90 (5) 15100 39 36 1000 (R,R)-DPEN NaOiPr (50/1) 97 (30) 17700 1236 1000 (S,S)-DPEN NaOiPr (50/1) 92 (30) 15200 26 39 1000 — NaOiPr(50/1) 96 (30) 13900 — ^(a)TOF = turnover frequency (moles of carbonylcompound converted to alcohol per mole of catalyst per hour) at 50%conversion.

TABLE 3 Catalytic transfer hydrogenation of ketones and aldehydes (0.1M)to alcohols with the complexes 1-21 using a ratio substrate/base(NaOiPr) of 50/1 Conversion Complex Substrate S/C % (min)  1benzaldehyde 1000 11 (10)  3 benzaldehyde 1000 10 (10) 4 + 5benzaldehyde 1000  8 (30) 6 + 7 benzophenone 1000 92 (10); 94 (30) 6 + 7benzaldehyde 1000 14 (60) 6 + 7 4-bromobenzaldehyde 1000 30 (60)  8benzaldehyde 1000 25 (60)  9 benzaldehyde 1000 20 (60) 204-bromobenzaldehyde 1000 97 (10) 20 (E)-2-methyl-3-phenylacrylaldehyde1000 93 (40) 21 benzophenone 1000 94 (30) 21 benzaldehyde 1000 98 (60)

EXAMPLE 38 Catalytic Reduction of Ketones with Complexes of Examples1-36 Using Molecular Hydrogen

The hydrogenation reactions were performed in an 8 vessels Endeavor Parrapparatus. The vessels were charge with the catalysts (2.5 μmol). Thevessels were closed, charged with 5 bar of N₂ and slowly vented fivetimes. The ketone (5 mmol), optionally ligand (5 μmol), the solvent (0.9mL) and 1 mL of a solution of t-BuOK 0.1 M were added. The vessels werecharged with 20 bar of H₂ and slowly vented four times. The vessel wascharged to 30 bars and heated to 70° C. (S/C=2000, S/B=50, L/C=2).

The molar ratio of substrate/catalyst varied from 2000/1 to 25000/1while the molar substrate/base ratio range from 10/1 to 100/1.

The hydrogen uptake was calculated by the apparatus and the results ofthe GC analysis at the end of the runs are shown in Tables 4 for thecatalytic reduction of acetophenone and in Table 5 for other substrates.

For the in situ reactions, the vessel was charge with the precursorcatalyst (2.5 μmol) and the corresponding ligand (5 μmol) (L/C=2/1) (seeTables 4 and 5).

TABLE 4 Catalytic hydrogenation (30 bar) of acetophenone to1-phenylethanol in the presence of the complexes 1-25 using f-BuOK orKOH as base conversion Complex S/C ligand solvent Base (S/B) % (h) 12000 — EtOH t-BuOK (50/1) 100 (16) 2 2000 — EtOH t-BuOK (50/1) 100 (16)3 2000 — EtOH t-BuOK (50/1) 100 (16) 8 2000 — EtOH t-BuOK (50/1) 100(16) 16 2000 — MeOH t-BuOK (20/1)  63 (16) 17 2000 — MeOH t-BuOK (20/1)100 (16) 20 2000 — EtOH t-BuOK (50/1)  61 (16) 20 2000 — MeOH t-BuOK(20/1)  25 (16) 21 2000 — EtOH t-BuOK (50/1)  43 (16) 21 2000 — MeOHt-BuOK (20/1)  13 (16) 22 2000 — EtOH t-BuOK (50/1)  42 (16) 22 2000 —MeOH t-BuOK (20/1)  36 (16) 25 2000 — EtOH t-BuOK (50/1)  72 (16) 252000 en EtOH t-BuOK (50/1) 100 (16) 25 2000 ampy EtOH t-BuOK (50/1) 100(16) 25 10000 en EtOH t-BuOK (50/1) 100 (16) 25 10000 ampy EtOH t-BuOK(50/1)  92 (16) 25 10000 en MeOH t-BuOK (50/1)  28 (16) 25 10000 ampyMeOH t-BuOK (50/1)  81 (16) 25 10000 en MeOH KOH (50/1)  27 (16) 2510000 ampy MeOH KOH (50/1)  91 (16) 25 25000 en MeOH KOH (50/1)  15 (16)25 25000 ampy MeOH KOH (50/1)  45 (16)

TABLE 5 Catalytic hydrogenation (30 bar) of ketones to alcohols in thepresence of the complexes 1-25 in ethanol using a ratio substrate/t-BuOKof 50/1 Conversion Complex Ketone S/C Ligand % (h) 2 tetralone 10000  8(16) 2 2′-Me-acetophenone 10000 100 (16) 2 4′-MeO-acetophenone 500 100(3) 2 4′-NO₂-acetophenone 10000  10 (16) 2 benzophenone 500 100 (3) 2benzoin 10000  5 (16) 2 2′-Cl-acetophenone 10000 100 (16) 8 tetralone10000  4 (16) 8 2′-Me-acetophenone 10000  28 (16) 8 4′-MeO-acetophenone500  75 (3) 8 4′-NO₂-acetophenone 10000  1 (16) 8 benzophenone 500 100(3) 8 benzoin 10000  9 (16) 8 2′-Cl-acetophenone 10000 100 (16) 16tetralone 10000  2 (16) 16 2′-Me-acetophenone 10000  76 (16) 164′-MeO-acetophenone 500  76 (3) 16 4′-NO₂-acetophenone 10000  5 (16) 16benzophenone 500  99 (3) 16 benzoin 10000  7 (16) 16 2′-Cl-acetophenone10000  84 (16) 25 2-octanone 1000 ampy  36 (3) 25 isobutyrophenone 1000ampy  61 (3) 25 tetralone 10000 ampy  7 (16) 25 tetralone 10000 en  3(16) 25 2′-Me-acetophenone 10000 ampy  38 (16) 25 2′-Me-acetophenone10000 en 100 (16)

1. A hexacoordinate complex of formula (1):[MXY_(a)(CO)L_(b)L′_(c)]W_(d)   (1) wherein M=Ru; a and b are 0; c and dare 1; X is C1-C20 carboxylate or C1-C20 alkoxide; W is halide, C1-C20carboxylate or C1-C20 alkoxide; L′ is a PNN compound of formula (V)

wherein R²¹-R²⁹ are, independently, H, a C1-C20 aliphatic group, or aC5-C20 aromatic group.
 2. A process for reducing a ketone or aldehyde toan alcohol, comprising reducing the ketone or aldehyde to an alcoholusing the hexacoordinate complex of formula (1) of claim 1 as a catalystby transfer hydrogenation or hydrogenation with molecular hydrogen. 3.The process of claim 2 comprising the following steps: (a) mixing thehexacoordinate complex of formula (1) as a catalyst with a solutioncomprising at least one base and at least one substrate that is a C3-C42ketone or a C2-C41 aldehyde, thereby obtaining a mixture; and (b)contacting said mixture with molecular H₂ or with at least onehydrogen-donor.
 4. The process according to claim 2, wherein in step (a)the base is potassium hydroxide, potassium carbonate or an alkali metalalkoxide; and in step (b) the mixture is contacted with molecularhydrogen.
 5. The process according to claim 4, wherein the base issodium iso-propoxide or potassium tert-butoxide.
 6. The processaccording to claim 2, wherein in step (a) the base is sodiumiso-propoxide and in step (b) the mixture is contacted with at least onehydrogen donor.
 7. The process according to claim 3, wherein the atleast one C3-C41 ketone is of formula R³⁰C(═O)R³¹, wherein R³⁰, R³¹ areindependently, a C1-C20 aliphatic group, a substituted aliphatic group,an aromatic group, a substituted aromatic group, or a heteroaromaticgroup, wherein optionally R³⁰ and R³¹ are linked to form a cycle.
 8. Theprocess according to claim 2, wherein the molar ratio substrate/catalystor pre-catalyst ranges from 1000/1 to 100000/1.
 9. The process accordingto claim 2, wherein the molar ratio substrate/base ranges from 10/1 to100/1.
 10. A process for the reduction of a carbonyl compound bytransfer hydrogenation or hydrogenation with molecular hydrogen, theprocess comprising the use of the hexacoordinate complex of formula (1)of claim 1.